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Background: Testicular Germ Cell Tumors (TGCT) are the most common cancer among young adult men. The TGCT histopathology is diverse, and the frequency of genomic alterations, along with their prognostic role, remains largely unexplored. Herein, we evaluate the mutation profile of a 15-driver gene panel and copy number variation of KRAS in a large series of TGCT from a single reference cancer center. Materials and methods: A cohort of 97 patients with TGCT, diagnosed at the Barretos Cancer Hospital, was evaluated. Real-time PCR was used to assess copy number variation (CNV) of the KRAS gene in 51 cases, and the mutation analysis was performed using the TruSight Tumor 15 (Illumina) panel (TST15) in 65 patients. Univariate analysis was used to compare sample categories in relation to mutational frequencies. Survival analysis was conducted by the Kaplan-Meier method and log-rank test. Results: KRAS copy number gain was a very frequent event (80.4%) in TGCT and presented a worse prognosis compared with the group with no KRAS copy gain (10y-OS, 90% vs. 81.5%, p = 0.048). Among the 65 TGCT cases, different variants were identified in 11 of 15 genes of the panel, and the TP53 gene was the most recurrently mutated driver gene (27.7%). Variants were also detected in genes such as KIT, KRAS, PDGFRA, EGFR, BRAF, RET, NRAS, PIK3CA, MET, and ERBB2, with some of them potentially targetable. Conclusion: Although larger studies incorporating collaborative networks may shed the light on the molecular landscape of TGCT, our findings unveal the potential of actionable variants in clinical management for applying targeted therapies.
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Resveratrol is a polyphenolic compound whose antitumor activity has been demonstrated in several types of cancer. However, there are few studies on its molecular mechanisms of action in bladder cancer. Therefore, we aimed to evaluate resveratrol activity in bladder tumour cells with different TP53 gene status. Cytotoxicity, cell proliferation, reactive oxygen species (ROS) production, cell migration, mutagenicity, and CDH1, CTNNBIP1, HAT1, HDAC1, MYC, and SMAD4 gene expression were evaluated. An increase in ROS after resveratrol treatment was accompanied by reduced cell viability and proliferation in all cell lines. In TP53 wild-type cells, the inhibition of cell migration was accompanied by CDH1 and SMAD4 modulation. In TP53 mutated cells, cell migration inhibition with CDH1 and CTNNB1P1 upregulation was observed. In conclusion, resveratrol has antiproliferative effect in bladder tumour cells and its mechanism of action occurred through ROS production, interference with cell cycle, and inhibition of cell migration, independent of TP53 status.
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BACKGROUND: Leiomyosarcoma is a rare malignant tumor of smooth muscle origin and represents 10-20% of all soft tissue sarcomas. Primary colon and rectal sarcomas constitute < 0.1% of all large bowel malignancies. In Li-Fraumeni syndrome, sarcomas are the second most frequent cancer (25%). Li-Fraumeni syndrome is a genetic disease with a familial predisposition to multiple malignant neoplasms. This syndrome has an autosomal dominant pattern of inheritance and high penetrance characterized by germline TP53 mutations. Patients with a history of cancer who do not meet all the "classic" criteria for Li-Fraumeni syndrome are considered to have Li-Fraumeni-like syndrome. To the best of our knowledge, this article is the first report of a patient with rectal leiomyosarcoma as the initial phenotypic manifestation of Li-Fraumeni-like syndrome. The authors also present a literature review. CASE PRESENTATION: A 67-year-old Brazilian woman underwent anterior rectosigmoidectomy and panhysterectomy secondary to rectal leiomyosarcoma. She subsequently developed carcinomatosis and died 2 years after the operation. Her family medical history consisted of a daughter who died at 32 years of age from breast cancer, a granddaughter diagnosed with adrenocortical carcinoma at 6 years of age and two siblings who died from prostate cancer. A genetic study was carried out to identify a pathogenic variant of Li-Fraumeni syndrome. In the DNA extracted from the peripheral blood leukocyte, restriction fragment length polymorphism was analyzed to search for mutations in the TP53 gene. The DNA sequencing identified the germline pathogenic variant p. R337H heterozygous in exon 10 of TP53. The patient was classified as having Li-Fraumeni-like syndrome. CONCLUSION: In patients with rectal leiomyosarcoma, it is advisable to investigate the family history of cancer and perform genetic studies to screen for Li-Fraumeni syndrome.
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Neoplasias do Córtex Suprarrenal , Carcinoma Adrenocortical , Leiomiossarcoma , Síndrome de Li-Fraumeni , Neoplasias Pélvicas , Neoplasias Retais , Masculino , Feminino , Humanos , Criança , Idoso , Síndrome de Li-Fraumeni/complicações , Síndrome de Li-Fraumeni/diagnóstico , Síndrome de Li-Fraumeni/genética , Leiomiossarcoma/diagnóstico , Leiomiossarcoma/genética , Leiomiossarcoma/cirurgia , Proteína Supressora de Tumor p53/genética , Neoplasias Retais/diagnóstico , Neoplasias Retais/genética , Neoplasias Retais/cirurgia , Neoplasias do Córtex Suprarrenal/complicações , Neoplasias do Córtex Suprarrenal/genética , Predisposição Genética para DoençaRESUMO
In Southern and Southeastern Brazil, there is a germline pathogenic variant with incomplete penetrance located in the oligomerization domain of TP53, c.1010G>A (p.Arg337His). Due to a founder effect, the variant is present in 0.3% of the general population of the region. Recently, this variant was identified in 4.4 and 8.9% of two apparently unselected, single center case series of Brazilian lung adenocarcinoma (LUAD) patients from the Southeastern and Central regions of the country, respectively. In the present study, our aim was to examine TP53 c.1010G>A allele and genotype frequencies in LUAD samples obtained from patients diagnosed in Southern Brazil. A total of 586 LUAD samples (tumor DNA) recruited from multiple centers in the region were tested, and the mutant allele was identified using TaqMan® assays in seven cases (7/586, 1.2%) which were submitted to next generation sequencing analyses for confirmation. Somatic EGFR mutations were more frequent in TP53 c.1010G>A carriers than in non-carriers (57.1 vs. 17.6%, respectively). Further studies are needed to confirm if TP53 c.1010G>A is a driver in LUAD carcinogenesis and to verify if there is a combined effect of EGFR and germline TP53 c.1010G>A. Although variant frequency was higher than observed in the general population, it is less than previously reported in LUAD patients from other Brazilian regions. Additional data, producing regional allele frequency information in larger series of patients and including cost-effectiveness analyses, are necessary to determine if TP53 c.1010G>A screening in all Brazilian LUAD patients is justified.
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El cáncer en pediatría es una entidad infrecuente. Se estima que más de un 10-15 % de los tumores son secundarios a una variante patogénica en un gen de predisposición al cáncer.Se conocen más de 100 genes de predisposición al cáncer y su asociación con síndromes o tumores aislados. Uno de los más descritos es el síndrome de Li-Fraumeni.Los pacientes con este síndrome tienen alto riesgo de desarrollar uno o más tumores. Su conocimiento permite realizar un protocolo de seguimiento del paciente y de sus familiares afectos, con el que detectar precozmente nuevos tumores y disminuir la morbimortalidad del tumor y de su tratamiento.Esta revisión pretende ser una guía útil para el pediatra. Utilizando como caso guía a una familia, se revisarán los motivos de sospecha de un síndrome de Li-Fraumeni, su diagnóstico clínico y genético, y el protocolo de seguimiento de los familiares portadores de la misma mutación
Pediatric cancer is rare. It is estimated that more than 10-15 % of tumors are secondary to a pathogenic variant in a cancer predisposition gene.More than 100 cancer predisposition genes and their association with syndromes or isolated tumors have been identified. Li-Fraumeni syndrome is one of those who have been most widely described.Patients with this syndrome present a high risk of developing one or more tumors. Its knowledge allows to establish a follow-up protocol for the patient and affected family members, so as to detect new tumors in an early manner and reduce tumor- and treatment-related morbidity and mortality.The objective of this review is to offer useful guidelines for pediatricians. Based on a family case, reasons for Li-Fraumeni syndrome suspicion, clinical and genetic diagnosis, and the follow-up protocol of family members who carry the same mutation will be reviewed.
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Humanos , Lactente , Pré-Escolar , Criança , Síndrome de Li-Fraumeni/diagnóstico , Pediatria , Síndromes Neoplásicas Hereditárias , Genes p53 , Síndrome de Li-Fraumeni/epidemiologiaRESUMO
Pediatric cancer is rare. It is estimated that more than 10-15 % of tumors are secondary to a pathogenic variant in a cancer predisposition gene. More than 100 cancer predisposition genes and their association with syndromes or isolated tumors have been identified. Li-Fraumeni syndrome is one of those who have been most widely described. Patients with this syndrome present a high risk of developing one or more tumors. Its knowledge allows to establish a follow-up protocol for the patient and affected family members, so as to detect new tumors in an early manner and reduce tumorand treatment-related morbidity and mortality. The objective of this review is to offer useful guidelines for pediatricians. Based on a family case, reasons for Li-Fraumeni syndrome suspicion, clinical and genetic diagnosis, and the follow-up protocol of family members who carry the same mutation will be reviewed.
El cáncer en pediatría es una entidad infrecuente. Se estima que más de un 10-15 % de los tumores son secundarios a una variante patogénica en un gen de predisposición al cáncer. Se conocen más de 100 genes de predisposición al cáncer y su asociación con síndromes o tumores aislados. Uno de los más descritos es el síndrome de Li-Fraumeni. Los pacientes con este síndrome tienen alto riesgo de desarrollar uno o más tumores. Su conocimiento permite realizar un protocolo de seguimiento del paciente y de sus familiares afectos, con el que detectar precozmente nuevos tumores y disminuir la morbimortalidad del tumor y de su tratamiento. Esta revisión pretende ser una guía útil para el pediatra. Utilizando como caso guía a una familia, se revisarán los motivos de sospecha de un síndrome de Li-Fraumeni, su diagnóstico clínico y genético, y el protocolo de seguimiento de los familiares portadores de la misma mutación.
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Síndrome de Li-Fraumeni , Criança , Predisposição Genética para Doença , Genótipo , Mutação em Linhagem Germinativa , Humanos , Síndrome de Li-Fraumeni/diagnóstico , Síndrome de Li-Fraumeni/genética , Proteína Supressora de Tumor p53/genéticaRESUMO
Silibinin, a natural compound extracted from milk thistle, has demonstrated antitumor properties in urinary bladder cancer cells; however, the role of TP53 gene in these effects is unclear. In order to better understand the molecular and antiproliferative mechanisms of this compound, urinary bladder cancer cells with different TP53 gene status, RT4 (low-grade tumor, wild TP53 gene), 5637 (high-grade tumor, Grade 2, mutated TP53 gene), and T24 (high-grade tumor, Grade 3, mutated TP53 gene) were treated with several concentrations of silibinin (1, 5, 10, 50, 100, and 150 µM). Cytotoxicity, prooxidant effect, morphological changes, cell migration, cell cycle progression, global methylation profile, and relative expression of HOXB3, c-MYC, PLK1, SMAD4, SRC, HAT, HDAC, and RASSF1A genes were evaluated. The silibinin presented cytotoxic and prooxidant effects in the three cell lines. In mutated TP53 cells, significant interference in cell migration and cell cycle arrest at the G2/M phase was observed. Additionally, silibinin induced global DNA hypomethylation in the highest grade tumor cells. For wild-type TP53 cells, a sub-G1 apoptotic population was present. Furthermore, there was modulation of gene expression responsible for cell growth (SMAD and c-MYC), migration (SRC), cell cycle kinetics (PLK1), angiogenesis (HOXB3), and of genes associated with epigenetic events such as DNA acetylation (HAT) and deacetylation (HDAC). In conclusion, the silibinin inhibited the urinary bladder tumor cell proliferation independently of TP53 status; however, cell cycle effects, gene expression changes, and alteration of cell migration are dependent on TP53 status. © 2020 Wiley Periodicals, Inc.
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Antineoplásicos Fitogênicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Silibina/farmacologia , Neoplasias da Bexiga Urinária/tratamento farmacológico , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Proteína Supressora de Tumor p53/genética , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/patologiaRESUMO
Li-Fraumeni syndrome (LFS) and Li-Fraumeni Like (LFL) are autosomal dominant cancer predisposition syndromes caused by pathogenic germline variants in the TP53 gene. Recent studies have shown that the incorporation of next-generation sequencing by using multigene panels in clinical practice has resulted in the frequent identification of variants of uncertain significance (VUS). Given that there is no established medical management for VUS carriers, the identification of these variants may cause confusion and anxiety for both patients and practitioners. Herein, we aimed to verify VUS frequency and review VUS classification and interpretation in 1844 patients submitted for comprehensive germline TP53 testing independent of clinical criteria. Variant characterization was done assessing clinical information whenever available, variant frequency in population databases, pathogenicity predictions using in silico tools and previous functional studies. All variants were classified based on the guidelines proposed by the American College of Medical Genetics and Genomics (2015) and by the Sherloc framework (2017). Of the twelve VUS (0.65%) identified in TP53, two were classified as likely pathogenic and two were classified as likely benign after re-evaluation, potentially resulting in significant management modification for the proband and relatives. This report cases highlights the challenges and impact of TP53 variant interpretation especially when there is no clear LFS/LFL phenotype.
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Aconselhamento Genético , Síndrome de Li-Fraumeni/genética , Proteína Supressora de Tumor p53/genética , Adulto , Idoso , Feminino , Frequência do Gene , Predisposição Genética para Doença , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
The antitumor activity of resveratrol, a polyphenolic compound found mainly in grapes, has been studied in several types of cancer. In bladder cancer, its antiproliferative effects have already been demonstrated; however, its mechanism of action is not completely understood. The aim of this study was to evaluate resveratrol antitumor activity (12.5, 25, 50, 100, 150, 200, and 250 µM) and its possible mechanisms of action in bladder tumor cells with different TP53 gene status (RT4, grade 1, TP53 wild type; 5637-grade 2 and T24-grade 3, TP53 mutated). Cell proliferation, clonogenic survival, morphological changes, cell cycle progression, apoptosis rates, genotoxicity, global methylation, immunocytochemistry for p53 and PCNA and relative expression profiles of the AKT, mTOR, RASSF1A, HOXB3, SRC, PLK1, and DNMT1 were evaluated. Resveratrol decreased cell proliferation and induced DNA damage in all cell lines. Regarding the long-term effects, resveratrol reduced the number of colonies in all cell lines; however, TP53 wild type cells were more resistant. Increased rates of apoptosis were found in the TP53 wild type cells and this was accompanied by AKT, mTOR, and SRC downregulation. In addition, the resveratrol antiproliferative effects in wild type TP53 cells were accompanied by modulation of the DNMT1 gene. In the TP53 mutated cells, cell cycle arrest at S phase with PLK1 downregulation was observed. Additionally, there was modulation of the HOXB3/RASSF1A pathway and nuclear PCNA reduction in the highest-grade cells. In conclusion, resveratrol has antiproliferative activity in bladder tumor cells; however, the mechanisms of action are dependent on TP53 status. Environ. Mol. Mutagen., 60:740-751, 2019. © 2019 Wiley Periodicals, Inc.
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Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Resveratrol/farmacologia , Proteína Supressora de Tumor p53/genética , Neoplasias da Bexiga Urinária/tratamento farmacológico , Apoptose/efeitos dos fármacos , Apoptose/genética , Proteínas de Ciclo Celular/biossíntese , Linhagem Celular Tumoral , Proliferação de Células/genética , Dano ao DNA/genética , Humanos , Antígeno Nuclear de Célula em Proliferação/biossíntese , Proteínas Serina-Treonina Quinases/biossíntese , Proteínas Proto-Oncogênicas/biossíntese , Pontos de Checagem da Fase S do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem da Fase S do Ciclo Celular/genética , Proteína Supressora de Tumor p53/biossíntese , Quinase 1 Polo-LikeRESUMO
BACKGROUND: The TP53 p.R337H germline mutation is highly prevalent among children with adrenocortical tumors (ACTs) from South and Southeast Brazil. However, the prevalence of other tumors of the Li-Fraumeni syndrome (LFS) and Li-Fraumeni-like syndrome (LFL) spectrum, the clinical outcomes and the potential tumor occurrence in relatives carrying this distinct TP53 mutation were not fully investigated. PATIENTS AND METHODS: We investigated tumor profile data and outcomes of individuals and their close relatives with the TP53 p.R337H germline mutation. A questionnaire and the Toronto protocol were used for evaluation of asymptomatic carriers of this TP53 mutation. RESULTS: The cohort of this study comprised 51 patients from 46 different families; 67% were female. All but one harbored the TP53 p.R337H mutation in heterozygous state; only one child was homozygous for this variant. Maternal allele inheritance occurred in 72% of the cases (p= 0,002). In pediatric group, ACT was the most common primary tumor at the diagnosis (55%; median age= 2 years). No patient of the pediatric group who initially presented with ACT developed a second primary tumor and 11% (n= 3) died due to complications related to the primary tumor (median follow-up time of 81.5 months, range= 3-378 months). In adult group, the main tumors at diagnosis were: adrenocortical carcinoma (ACC) (23%; median age= 29.5 years), breast cancer (12%; median age= 38.5 years), soft tissue sarcoma (8%; median age= 50.3 years) and choroid plexus carcinoma (CPC) (2%; median age= 18 years). Among adult patients who were diagnosed with ACC as the first primary tumor, all presented with aggressive disease as per histologic and clinical criteria at diagnosis, and 75% of patients died (median follow-up time of 19 months, range= 1-69 months). Five adult patients (22%) had a second primary tumor, including bronchoalveolar lung cancer (2 cases), ACC, uterine cervical carcinoma and fibrosarcoma. The diagnosis of these tumors was established from 8 to 36 months after the first primary tumor. Three families presented more than one case of ACT. Nine malignant neoplasms were diagnosed in asymptomatic carriers using Toronto protocol. CONCLUSIONS: This study confirms a high frequency of TP53 p.R337H mutation in pediatric group with ACT. In addition, we observed the occurrence of other tumors of LFS/LFL spectrum and a difference in the aggressiveness of ACTs depending on the age group in which they were diagnosed. The predominance of maternal mutated allele inheritance was first demonstrated in the affected Brazilian's families.
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Neoplasias do Córtex Suprarrenal/genética , Síndrome de Li-Fraumeni/genética , Proteína Supressora de Tumor p53/genética , Adolescente , Neoplasias do Córtex Suprarrenal/epidemiologia , Adulto , Brasil/epidemiologia , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Mutação em Linhagem Germinativa , Humanos , Lactente , Síndrome de Li-Fraumeni/epidemiologia , Masculino , Pessoa de Meia-Idade , Mutação Puntual , Adulto JovemRESUMO
Resumen: El síndrome de Li-Fraumeni (SLF) es una enfermedad hereditaria autosómica dominante con elevada penetrancia, que se caracteriza por la aparición precoz de múltiples tumores en un individuo y una marcada agregación familiar. Aproximadamente el 70% de los pacientes que cumplen criterios clínicos para su diagnóstico son portadores de la mutación germinal del gen TP53 localizado en el cromosoma 17p13. El gen TP53 es un supresor tumoral que cumple una importante función en el control de la estabilidad genómica. Se estima que el riesgo de desarrollar cáncer es del 50 % para las mujeres a los 31 años de edad y para los hombres a los 46 años y cerca del 100 % para ambos sexos a los 70 años. El curso clínico de la enfermedad es similar que en pacientes sin SLF a excepción de la edad más temprana al diagnóstico. Presentamos el caso de una paciente de 31 años a la que se diagnostica un condrosarcoma pelviano tratado con cirugía y al momento de la recidiva, aproximadamente 8 meses después, un cáncer de mama localizado. En otro miembro de su familia se había identificado la mutación 375G>C en el gen TP53 mediante secuenciación Sanger, la cual fue detectada posteriormente en nuestra paciente. Se discuten aspectos particulares del manejo como la minimización de la exposición a la radioterapia (por reportes de tumores malignos en zonas irradiadas) y el especial manejo de la repercusión del diagnóstico a nivel de los otros integrantes de la familia.
Abstract: The Li-Fraumeni syndrome (SLF) is a highly penetrant condition with an autosomal dominant inheritance pattern, characterized by an early onset of multiple tumors in a subject and a marked familial occurrence. About 70 % of patients meeting clinical criteria for diagnosis of the disease carry the germline mutation of TP53 gene located in chromosome 17p13. TP53 is a tumor suppressor gene known for its major role in genome stability control. It has been estimated that risk of cancer development is 50 % for women at the age of 31 and for men at the age of 46 and nearly 100 % for both men and women at 70 years of age. Except at earlier ages of diagnosis, the clinical course of the disease for healthy patients and for patients suffering SLF shows similarities. We present the case of a 31-year-old patient diagnosed both with pelvic chondrosarcoma treated surgically and localized breast cancer during relapse, about 8 months later. By Sanger sequencing, mutation 375G>C had been identified in TP53 gene in another family member, and said mutation was later detected in our patient. We discuss particular aspects of treatment procedures, such as minimizing radiotherapy exposure (due to reports of malignancies in radiated areas) and the special management of diagnosis implications for other family members.
Resumo: A síndrome de Li-Fraumeni (SLF) é uma doença hereditária autorexistente dominante com pena de penetração, que caracteriza a aparição precoz de múltiplos tumores em um indivíduo e uma coletânea familiar. Aproximadamente o 70% dos pacientes com critérios clínicos para o diagnóstico em crianças portadores da mutação germinal do gen TP53 localizado no cromosoma 17p13. El gen TP53 é um tumor tumoral que cumple uma função importante no controle da estabilização genómica. Se estima que o riesgo do desengate faz dos 50% para as mulheres aos 31 anos de idade e para os 40 anos e cerca de 100% para ambos os sexos aos 70 anos. O curso clínico da doença é semelhante ao que ocorre com a SLF a exceção da doença mais tem sido diagnosticada. Presentamos o caso de um paciente de 31 años que diagnostica um paciente de pélvico com relato ao momento da recidiva, aproximadamente 8 meses depois, em um lugar de mama próximo. En otio miembro de la familia se habiocuident to the mutación 375G> C en el gen TP53 por secuenciación Sanger, a cual fue detectada em recente paciente. A discussão foi feita sobre os aspectos do tratamento com a minimização da exposição à radioterapia (por tumores malignos em zonas irradiadas) e o especial manejo da repercussão do diagnóstico a nível dos otros integrantes da familia
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Li-Fraumeni syndrome is a rare hereditary cancer predisposition syndrome associated with germline pathogenic variants in TP53 gene. The phenotype may vary from classical to variant forms, known as Li-Fraumeni-like phenotypes. We searched for pathogenic variants in TP53 in a 14 year-old female diagnosed with fibrolamellar hepatocellular carcinoma, a rare subtype of hepatocellular carcinoma. The proband is a heterozygote carrier of the TP53 c.467G>A (p.Arg156His) in exon 5, and her mother is an asymptomatic carrier. Analysis of tumor DNA disclosed an additional somatic mutation in TP53, c.461G>A; p.Gly154Asp. The TP53 germline and somatic pathogenic variants may have acted as possible driver mutations, resulting in genomic instability and tumor development. The fibrolamellar subtype of hepatocellular carcinoma may be part of the broad spectrum of tumors associated with Li-Fraumeni phenotype.
Assuntos
Carcinoma Hepatocelular/genética , Síndrome de Li-Fraumeni/genética , Neoplasias Hepáticas/genética , Proteína Supressora de Tumor p53/genética , Adolescente , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/patologia , Análise Mutacional de DNA , Feminino , Testes Genéticos , Mutação em Linhagem Germinativa , Humanos , Fígado/patologia , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/patologia , LinhagemRESUMO
Li-Fraumeni syndrome (LFS) is a rare, autosomal dominant, hereditary cancer predisposition disorder. In Brazil, the p.R337H TP53 founder mutation causes the variant form of LFS, Li-Fraumeni-like syndrome. The occurrence of cancer and age of disease onset are known to vary, even in patients carrying the same mutation, and several mechanisms such as genetic and epigenetic alterations may be involved in this variability. However, the extent of involvement of such events has not been clarified. It is well established that p53 regulates several pathways, including the thymine DNA glycosylase (TDG) pathway, which regulates the DNA methylation of several genes. This study aimed to identify the DNA methylation pattern of genes potentially related to the TDG pathway (CDKN2A, FOXA1, HOXD8, OCT4, SOX2, and SOX17) in 30 patients with germline TP53 mutations, 10 patients with wild-type TP53, and 10 healthy individuals. We also evaluated TDG expression in patients with adrenocortical tumors (ADR) with and without the p.R337H TP53 mutation. Gene methylation patterns of peripheral blood DNA samples assessed by pyrosequencing revealed no significant differences between the three groups. However, increased TDG expression was observed by quantitative reverse transcription PCR in p.R337H carriers with ADR. Considering the rarity of this phenotype and the relevance of these findings, further studies using a larger sample set are necessary to confirm our results.
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Humanos , Antirreumáticos/efeitos adversos , Artrite Reumatoide/tratamento farmacológico , Produtos Biológicos/efeitos adversos , Antirreumáticos/uso terapêutico , Produtos Biológicos/uso terapêutico , Medicina Baseada em Evidências/métodos , Neoplasias/induzido quimicamente , Infecções Oportunistas/induzido quimicamente , Guias de Prática Clínica como Assunto , Medição de Risco/métodos , Fator de Necrose Tumoral alfa/antagonistas & inibidoresRESUMO
Since the first studies reporting the TP53 p.R337H mutation as founder mutation in Southern and Southeastern Brazil, there has been controversy on its origin. Preliminary analysis of a small subset of Brazilian mutation carriers revealed that the haplotype incided on a Caucasian background. The vast majority of carriers identified today reside in Brazil or, if identified in other countries, are Brazilian immigrants. To our knowledge, the only two exceptions of carriers without a recognizable link with Brazil are two European families, from Portugal and Germany. Haplotype analysis in the Portuguese family revealed the same haplotype identified in Brazilian individuals, but in the German family, a distinct haplotype was found. Knowing that a significant proportion of women with breast cancer (BC) in Southern Brazil are p.R337H carriers, we analyzed p.R337H in a Portuguese cohort of women diagnosed with this disease. Median age at diagnosis among the first 573 patients tested was 60 years and 100 (17.4%) patients had been diagnosed at or under the age of 45 years. Mutation screening failed to identify the mutation in the 573 patients tested. These results are in contrast with the mutation frequency observed in a study including 815 BC-affected women from Brazil, in which carrier frequencies of 12.1 and 5.1% in pre- and postmenopausal women were observed, respectively. These findings suggest that the Brazilian founder mutation p.R337H, the most frequent germline TP53 mutation reported to date, is not a common germline alteration in Portuguese women diagnosed with BC.
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Neoplasias da Mama/genética , Predisposição Genética para Doença , Mutação , Proteína Supressora de Tumor p53/genética , Adulto , Feminino , Humanos , Síndrome de Li-Fraumeni/genética , Pessoa de Meia-Idade , Portugal , População BrancaRESUMO
Introduction: The tumor protein p53 gene (TP53) is a constant target of investigation in cancer pathogenesis. Analysis by immunohistochemistry provides limited data about p53 in oral carcinogenesis, and TP53 sequencing can contribute to this analysis. However, obtaining high-quality and contamination-free deoxyribonucleic acid (DNA) for a proper amplification can be a difficult task when using paraffin-embedded tissues. Objective: Standardize DNA extraction, polymerase chain reaction (PCR) amplification and DNA sequencing techniques for TP53 mutation analysis. Material and methods: Thirty-nine cases of oral squamous cell carcinoma (OSCC) were selected from the Pathology Division of Instituto Nacional de Câncer (Inca). The DNA extraction method used was the QIAamp® DNA minikit® system. After DNA quantification by spectrophotometry, 250 ng of genetic material obtained from TP53 gene were amplified by PCR for exon 2 and by nested PCR for exon 6. Out of the total sample, 11 cases were selected for exon 2 sequencing. Results: The DNA samples presented mean concentration of 119.74 ± 88.86 ng/µl (28.9-556.4) and purity of 1.69 ± 0.18 (1-1.9). Thirty-three (84.6%) samples were amplified for exon 2, and all samples for exon 6 (39/100%). Readable sequencing data were obtained in 10 (90.9%) cases. Conclusion: Optimization of conditions for TP53 sequencing was obtained, and this will facilitate the analysis of mutations in paraffin-embedded tissues, allowing molecular retrospective studies...
Introdução: O gene TP53 (proteína tumoral p53) é alvo constante de investigação na patogênese do câncer. A imuno-histoquímica fornece dados limitados na análise de p53 no processo da carcinogênese bucal e o sequenciamento de TP53 pode contribuir nessa investigação. Contudo, a obtenção de ácido desoxirribonucleico (DNA) com qualidade para amplificação e livre de contaminação pode constituir uma tarefa difícil na utilização de material parafinado. Objetivo: Padronizar as técnicas de extração de DNA, amplificação por reação em cadeia da polimerase (PCR) e sequenciamento para a análise de mutações em TP53. Material e métodos: Foram selecionados 39 casos de carcinomas de células escamosas bucal da Divisão de Patologia do Instituto Nacional de Câncer (Inca). O DNA foi extraído utilizando o sistema comercial QIAamp® DNA minikit®. Após quantificação do DNA por espectrofotometria, 250 ng de amostra foram amplificados pela técnica de PCR para o éxon 2 e por nested PCR para o éxon 6 do gene TP53. Da amostra total, 11 casos foram selecionados para a padronização da reação de sequenciamento do éxon 2. Resultados: As amostras de DNA apresentaram concentração média de 119,74 ng/µl ± 88,86 (28,9-556,4 ng/µl) e pureza de 1,69 ± 0,18 (1-1,9). Do total das amostras analisadas, 33 (84,6%) foram amplificadas para o éxon 2, e todas (39/100%), para o éxon 6. No sequenciamento do éxon 2 obtiveram-se sequências passíveis de leitura em 10 (90,9%) casos. Conclusão: A otimização das condições para o sequenciamento de TP53 foi obtida, o que facilitará a análise de mutações em tecidos parafinados, permitindo...
Assuntos
Humanos , Análise de Sequência de DNA/métodos , Carcinoma de Células Escamosas/genética , /genética , Mutação/genética , Inclusão em Parafina , Neoplasias Bucais/genética , Reação em Cadeia da PolimeraseRESUMO
Introducción: El cáncer colorrectal (CCR) es una de las neoplasias más comunes en el mundo; especialmente,en los países desarrollados. En Colombia, la incidencia del CCR ocupa el cuarto lugar en hombres ymujeres; el CCR tiene una gran heterogeneidad genética. Objetivo: Determinar la presencia de mutacionesen los exones 5-8 del gen TP53 en tumores colorrectales, mediante el secuenciamiento directo. Métodos:Muestras con diagnóstico histopatológico de CCR esporádico se dividieron en dos grupos. El Grupo I fue de 30 muestras de tumores a partir de biopsias frescas, y el Grupo II, de 46 muestras de tejidos tumorales embebidos en bloques de parafi na. El análisis de mutaciones se realizó en los exones 5-8 del gen TP53,empleando las técnicas de PCR y de secuenciamiento directo. Resultados: Se encontró una baja frecuenciade mutaciones en el gen TP53, del 4,4%; las mutaciones detectadas fueron sin sentido; además, fueronidentifi cados dos polimorfi smos que segregan juntos. Todas las mutaciones y los polimorfi smos se detectaron en las muestras del grupo I. La mayoría de las muestras analizadas se hallaban en un estado avanzado del cáncer. Conclusiones: La baja frecuencia obtenida de mutaciones en TP53 permite sugerir la existencia de alteraciones en otras vías genéticas, relacionadas con la carcinogénesis colorrectal, como las vías de MSI y de CIN, así como la epigenética; dichas alteraciones no podrían excluirse en las muestras evaluadas. Los estudios moleculares en muestras de tejidos embebidos en parafi na presentan difi cultades para los análisis genéticos. La caracterización molecular del CCR es importante para conocer el espectro de mutaciones y de variantes moleculares presentes en la población observada.
Introduction: Colorectal cancer (CRC) is one of the most common malignancies in the world, especially indeveloped countries. In Colombia, the incidence of CRC ranks fourth in men and women. CRC has greatgenetic heterogeneity. Purpose: The purpose of this study was to determine the presence of mutations inexons 5 to 8 of the TP53 gene in colorectal tumors by direct sequencing. Patients and Methods: Samples with histopathological diagnoses of sporadic CRC were divided into two groups. Group I included 30 tumor samples from fresh biopsies and Group II included 46 tumor tissue samples embedded in paraffi n blocks. Mutational analysis was performed for exons 5 through 8 of the TP53 gene using PCR and direct sequencing.Results: The frequency of TP53 mutations was only 4.4%, and mutations that were detected were nonsense mutations. In addition, two polymorphisms that segregate together were identifi ed. All mutations and polymorphismswere detected in samples from Group I. Most of the samples were in advanced stages of cancer.Conclusions: The low frequency of mutations in TP53 suggests the existence of alterations on other related genetic pathways in colorectal carcinogenesis. These could include MSI pathways, CIN and epigenetics. Such alterations could not be excluded in the samples tested. Molecular studies of tissue samples embedded inparaffi n are diffi cult to analyze genetically. Molecular characterization of CRC is important for determining the spectrum of mutations and molecular variants present in our population.
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Humanos , Masculino , Feminino , Adulto Jovem , Pessoa de Meia-Idade , Neoplasias Colorretais , Heterogeneidade Genética , NeoplasiasRESUMO
The genetic heterogeneity presented by different cell lines derived from glioblastoma (GBM) seems to influence their responses to antitumoral agents. Although GBM tumors present several genomic alterations, it has been assumed that TP53, frequently mutated in GBM, may to some extent be responsible for differences in cellular responses to antitumor agents, but this is not clear yet. To directly determine the impact of TP53 on GBM response to ionizing radiation, we compared the transcription profiles of four GBM cell lines (two with wild-type (WT) TP53 and two with mutant (MT) TP53) after 8Gy of gamma-rays. Transcript profiles of cells analyzed 30 min and 6h after irradiation showed that WT TP53 cells presented a higher number of modulated genes than MT TP53 cells. Our findings also indicate that there are several pathways (apoptosis, DNA repair/stress response, cytoskeleton organization and macromolecule metabolic process) in radiation responses of GBM cell lines that were modulated only in WT TP53 cells (30 min and 6h). Interestingly, the majority of differentially expressed genes did not present the TP53 binding site, suggesting secondary effects of TP53 on transcription. We conclude that radiation-induced changes in transcription profiles of irradiated GBM cell lines mainly depend on the functional status of TP53.
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Biomarcadores/metabolismo , Perfilação da Expressão Gênica , Glioblastoma/genética , Mutação/genética , Radiação Ionizante , Proteína Supressora de Tumor p53/genética , Adulto , Imunofluorescência , Glioblastoma/metabolismo , Glioblastoma/patologia , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sarcômeros/química , Sarcômeros/metabolismo , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/deficiênciaRESUMO
TP53 is the most commonly mutated gene in human cancers. Approximately 90% of mutations in this gene are localized between domains encoding exons 5 to 8. The aim of this investigation was to examine the ability of the low density DNA microarray with the assistance of double tandem hybridization platform to characterize TP53 mutational hotspots in exons 5, 7, and 8 of the TP53. Nineteen capture probes specific to each potential mutation site were designed to hybridize to specific site. Virtual hybridization was used to predict the stability of hybridization of each capture probe with the target. Thirty-three DNA samples from different sources were analyzed for mutants in these exons. A total of 32 codon substitutions were found by DNA sequencing. 24 of them a showed a perfect correlation with the hybridization pattern system and DNA sequencing analysis of the regions scanned. Although in this work we directed our attention to some of the most representative mutations of the TP53 gene, the results suggest that this microarray system proved to be a rapid, reliable, and effective method for screening all the mutations in TP53 gene.
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Introducción. Las alteraciones cromosómicas numéricas y estructurales son comunes en las neoplasias gastrointestinales; estas alteraciones se originan por la inestabilidad cromosómica que ocurre durante el desarrollo del cáncer, afectando la expresión de diversos genes como protooncógenes, genes supresores de tumores y genes de reparación.Objetivo. Evaluar las aneuploidías del cromosoma 17 y deleción del gen TP53 en tumores gastrointestinales primarios, mediante la técnica del FISH bicolor. Muestras y métodos. Se analizaron 15 muestras de tumores gastrointestinales primarios, se disociaron mecánica y enzimáticamente con colagenasa para obtener núcleos interfásicos. El FISH bicolor se realizó con sondas marcadas con fluorocromos para el centrómero del cromosoma 17 y para el locus 17p13.1 del gen TP53. Se analizaron 100 núcleos por cada muestra.Resultados. Se encontró que el 33,3% (5/15) de las muestras tenía aneuploidías para el cromosoma 17; la monosomía fue detectada en todos los casos (5/5). La mayoría de las muestras tenía subpoblaciones de núcleos heterogéneos (mosómicos, disómicos, trisómicos y tetrasómicos). El 93,3% (14/15) de los tumores tenían deleción del gen TP53. El estudio histopatológico mostró que 14 de las 15 muestras presentaban un estado avanzado del cáncer.Conclusiones. Se demostró un imbalance entre las señales del centrómero del cromosoma 17 y del gen TP53 por núcleo mediante el FISH bicolor. Aneuploidías del cromosoma 17 y deleciones en el locus 17p13.1 del gen TP53 son alteraciones muy frecuentes en tumores gastrointestinales. El FISH bicolor permite evidenciar la heterogeneidad genética intratumoral que se presenta en el desarrollo del cáncer.
Introduction. Numerical and structural chromosome aberrations are common in gastrointestinal cancers; these are originated by chromosomal Instability that happens during development of cancer. Thus, the expression of many genes is affected, such as protooncogene, tumor suppressor genes and repair genes. Aims. To evaluate aneuploidy of chromosome 17 and TP53 gene deletions in primary gastrointestinal tumors by dual- color fluorescence in situ hybridization (FISH).Samples and methods. 15 primary gastrointestinal tumor samples were analyzed, which were mechanically and enzimatically disaggregated with 0.2% collagenase in order to obtain interphase nuclei. Dual-color FISH assays was performed using direct fluorescent labeling probes for the chromosome 17 centromere and TP53 gene (17p13.1). Hybridized signals were counted in 100 interphase nuclei by each case.Results. Aneuploidy of chromosome 17 was found in 33.3% (5/15) of the samples. Monosomy was detected in 100% (5/5) of cases with aneuploidies. Most of tumor samples exhibited heterogeneous clones that were monosomic, disomic, trisomic and occasionally tetrasomic. The TP53 deletion was found in 93.3% (14/15) of the analyzed samples. The histopathological study showed that 14 out of 15 tumors samples displayed an advance stage of tumorigenesis.Conclusions. We found an imbalance of signals for chromosome 17 and TP53 per nucleus. Aneuploidy of chromosome 17 and TP53 gene deletion are very frequent aberrations in gastrointestinal tumors. Dual-color FISH analysis allow detect intratumoral genetic heterogeneity that had occurred in development of cancer.
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Humanos , Masculino , Feminino , Adulto , Idoso , Aneuploidia , Neoplasias Gastrointestinais , Heterogeneidade GenéticaRESUMO
O linfoma de Burkitt (LB) surge a partir de uma célula do centro germinativo que perde o controle da proliferação devido à ativação do gene c-myc. A resistência à apoptose é uma causa importante da falha à quimioterapia na maioria dos cânceres e também no LB. A taxa alta de apoptose observada no LB em fases iniciais da gênese do tumor é seguida pelo desenvolvimento subseqüente de inativação de vias que levam à apoptose da célula. Uma importante via que se encontra alterada no LB é a via mediada pela proteína p53. Essa via é importante para o controle da proliferação celular em resposta ao dano no DNA. Dados da literatura mostram uma correlação entre mutações do gene TP53 com resistência ao tratamento. No entanto, alguns estudos têm demonstrado que diferentes tipos de mutações podem conferir respostas diferentes das células à quimioterapia. Isso tem sido observado em nossos estudos que mostram que linhagens celulares do LB com mutações diferentes da p53 apresentam uma resposta diferenciada à apoptose induzida por drogas que atuam por essa via, como, por exemplo, a doxorrubicina. Diferentes tipos de mutações conferem fenótipos funcionais distintos, embora nem sempre ocorra uma perda da função, o que pode ser um importante componente da resistência à quimioterapia no LB. Nesse artigo revisamos a literatura com relação à resposta ao tratamento no LB e discutimos o papel das mutações do gene TP53 na resistência à quimioterapia nesses tumores.
Burkitt's lymphoma (BL) originates from a germinative centre cell that loses proliferation control due to activation of the c-myc gene. Apoptosis resistance is a major cause of chemotherapy failure in most kinds of cancers, including BL. The high rate of apoptosis seen in the early steps of genesis of BL is followed by a subsequent development of inactivation of pathways leading to cell death by apoptosis. A major pathway known to be altered in BL is the one mediated by the p53 protein. This pathway is important to control cell proliferation in response to DNA damage. Data from the literature show a correlation between TP53 gene mutations and treatment resistance. However, some studies have demonstrated that distinct types of mutations have the ability to confer different cell responses to chemotherapy. We found that BL cell lines bearing distinct mutations of p53 also present different responses to drug-induced apoptosis, when using drugs that act through this pathway, such as doxorubicin. Different types of mutations might confer distinct functional phenotypes. Loss of function does not always occur which may be considered an important component of chemotherapy resistance in BL. In this article we review publications regarding the response to treatment in BL while we discuss the role of TP53 gene mutations in chemotherapy resistance of these tumors.