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1.
Front Oncol ; 14: 1350162, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38544834

RESUMEN

Background: Breast and prostate cancers are the most common malignancies diagnosed in women and men respectively, and present with great clinical heterogeneity, even in tumors with the same histology and same site of origin. Somatic and germline molecular alterations in DNA may have prognostic and predictive impact, influencing response to therapies and overall survival. Our aim is to characterize the somatic and germline genomic landscape of women with locally advanced HER2-positive breast cancer and men with metastatic prostate cancer in Brazil. Secondarily, we aim to identify genetic variants associated with tumor prognosis and treatment response, identify patients carrying pathogenic alterations in cancer-predisposing genes, and characterize the genetic ancestry of the population included in the study. Methods: This observational multicenter cohort study will include 550 adult patients from the five macro-regions of Brazil, divided into two arms: 1) breast cancer and 2) prostate cancer. Clinical and pathological data will be collected, as well as DNA samples from peripheral blood and tumor samples. In arm 1, the inclusion criteria are a histological diagnosis of breast carcinoma with overexpression of HER-2, clinical stage II or III, and current neoadjuvant treatment with chemotherapy plus trastuzumab. In arm 2, the criterion is a histological diagnosis of prostate adenocarcinoma, clinical stage IV. Whole-exome sequencing (WES) will be performed to identify variants that may be drivers and/or actionable in a specific patient or tumor. These variants will be interpreted and classified according to their population frequencies, in silico predictors, functional studies, and literature data, following international guidelines proposed by expert societies. Discussion: This trial will contribute to the construction of a robust database that should provide a better understanding of the genomic profile of patients with breast and prostate cancer in Brazil. Considering the miscegenation of the Brazilian population, knowledge generated from these data will have implications for future studies of this specific population. Clinical trial registration: [clinicaltrial.gov], identifier [NCT05306600].

2.
Genet Mol Biol ; 46(3 Suppl 1): e20230133, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38252059

RESUMEN

The TP53 3'UTR variant rs78378222 A>C has been detected in different tumor types as a somatic alteration that reduces p53 expression through modification of polyadenylation and miRNA regulation. Its prevalence is not yet known in all tumors. Herein, we examine tumor tissue prevalence of rs7837822 in Brazilian cohorts of patients from south and southeast regions diagnosed with lung adenocarcinoma (LUAD, n=586), sarcoma (SARC, n=188) and uterine leiomyoma (ULM, n=41). The minor allele (C) was identified in heterozygosity in 6/586 LUAD tumors (prevalence = 1.02 %) and none of the SARC and ULM samples. Additionally, next generation sequencing analysis revealed that all variant-positive tumors (n=4) with sample availability had additional pathogenic or likely pathogenic somatic variants in the TP53 coding regions. Among them, 3/4 (75 %) had the same pathogenic or likely pathogenic sequence variant (allele frequency <0.05 in tumor DNA) namely c.751A>C (p.Ile251Leu). Our results indicate a low somatic prevalence of rs78378222 in LUAD, ULM and SARC tumors from Brazilian patients, which suggests that no further analysis of this variant in the specific studied regions of Brazil is warranted. However, these findings should not exclude tumor molecular testing of this TP53 3'UTR functional variant for different populations.

3.
JCO Glob Oncol ; 9: e2300006, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38060977

RESUMEN

PURPOSE: To evaluate cancer risk factors among cancer cases and controls from Southern Brazil, to analyze a multigene hereditary panel testing (MGPT, 26 genes) for breast cancer (BC) and colorectal cancer (CCR) cases diagnosed age younger than 50 years and to characterize them for hereditary cancer syndrome (HCS) phenotypes. METHODS: A case-control (matched by age group and sex) study was conducted on regional cancer. Data on exposure factors and first-/second-degree family history of cancer (1/2FHC) were collected. The MGPT was performed using Illumina next-generation sequencing technology. RESULTS: A total of 1,007 cases and 1,007 controls were included. The most frequent cancers were BC (n = 311), CCR (n = 147), prostate (n = 132), and lung cancers (n = 89). It was independently associated with cancer, 1/2FHC, tobacco consumption (TC), pesticide exposure (PE), solvent/glue exposure, and BMI <24. BC was associated with 1/2FHC, TC, and hormone replacement therapy use; CCR with 1/2FHC, TC, and BMI <24; prostate cancer with 1/2FHC, TC, and alcohol consumption; and lung cancer with 1/2FHC, TC, PE, and BMI <24. MGPT identified pathogenic/likely pathogenic mutations in 24 (32%) women with BC and in three (18%) women and four (24%) men diagnosed with CCR at under 50 years. Among the tested patients under 50 years with diagnosed BC and CCR, 98.6% and 97% present criteria for HCS, respectively. CONCLUSION: This study confirmed the association of several factors associated with BC, CCR, prostate, and lung cancers and reinforced the importance of evaluating FHC and genetic testing, especially for patients under 50 years with diagnosed BC or CCR. A better understanding of population-specific cancer risk factors builds on sustainable data for developing prevention strategies. These efforts increase the commitment to early detection and surveillance.


Asunto(s)
Neoplasias de la Mama , Neoplasias Pulmonares , Humanos , Femenino , Persona de Mediana Edad , Masculino , Estudios de Casos y Controles , Brasil/epidemiología , Neoplasias de la Mama/diagnóstico , Factores de Riesgo
4.
PLoS One ; 16(9): e0251639, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34529667

RESUMEN

Li-Fraumeni syndrome (LFS) is an autosomal dominant cancer predisposition syndrome caused by pathogenic germline variants in the TP53 gene, characterized by a predisposition to the development of a broad spectrum of tumors at an early age. The core tumors related to LFS are bone and soft tissue sarcomas, premenopausal breast cancer, brain tumors, adrenocortical carcinomas (ACC), and leukemias. The revised Chompret criteria has been widely used to establish clinical suspicion and support TP53 germline variant testing and LFS diagnosis. Information on TP53 germline pathogenic variant (PV) prevalence when using Chompret criteria in South America and especially in Brazil is scarce. Therefore, the aim of this study was to characterize patients that fulfilled these specific criteria in southern Brazil, a region known for its high population frequency of a founder TP53 variant c.1010G>A (p.Arg337His), as known as R337H. TP53 germline testing of 191 cancer-affected and independent probands with LFS phenotype identified a heterozygous pathogenic/likely pathogenic variant in 26 (13.6%) probands, both in the DNA binding domain (group A) and in the oligomerization domain (group B) of the gene. Of the 26 carriers, 18 (69.23%) were R337H heterozygotes. Median age at diagnosis of the first tumor in groups A and B differed significantly in this cohort: 22 and 2 years, respectively (P = 0.009). The present study shows the clinical heterogeneity of LFS, highlights particularities of the R337H variant and underscores the need for larger collaborative studies to better define LFS prevalence, clinical spectrum and penetrance of different germline TP53 pathogenic variants.


Asunto(s)
Mutación de Línea Germinal , Síndrome de Li-Fraumeni/patología , Análisis de Secuencia de ADN/métodos , Proteína p53 Supresora de Tumor/genética , Adolescente , Adulto , Brasil , Niño , Preescolar , Femenino , Humanos , Lactante , Síndrome de Li-Fraumeni/genética , Masculino , Persona de Mediana Edad , Penetrancia , Fenotipo , Prevalencia , Adulto Joven
5.
Front Genet ; 12: 606537, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33603772

RESUMEN

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.

6.
BMC Cancer ; 20(1): 1069, 2020 Nov 09.
Artículo en Inglés | MEDLINE | ID: mdl-33167923

RESUMEN

BACKGROUND: Melanoma is the most aggressive type of skin cancer and is associated with environmental and genetic risk factors. It originates in melanocytes, the pigment-producing cells. Single nucleotide polymorphisms (SNPs) in pigmentation genes have been described in melanoma risk modulation, but knowledge in the field is still limited. METHODS: In a case-control approach (107 cases and 119 controls), we investigated the effect of four pigmentation gene SNPs (TYR rs1126809, HERC2 rs1129038, SLC24A5 rs1426654, and SLC45A2 rs16891982) on melanoma risk in individuals from southern Brazil using a multivariate logistic regression model and multifactor dimensionality reduction (MDR) analysis. RESULTS: Two SNPs were associated with an increased risk of melanoma in a dominant model: rs1129038AA and rs1426654AA [OR = 2.094 (95% CI: 1.106-3.966), P = 2.3 10- 2 and OR = 7.126 (95% CI: 1.873-27.110), P = 4.0 10- 3, respectively]. SNP rs16891982CC was associated with a lower risk to melanoma development in a log-additive model when the allele C was inherited [OR = 0.081 (95% CI: 0.008-0.782), P = 3 10- 2]. In addition, MDR analysis showed that the combination of the rs1426654AA and rs16891982GG genotypes was associated with a higher risk for melanoma (P = 3 10- 3), with a redundant effect. CONCLUSIONS: These results contribute to the current knowledge and indicate that epistatic interaction of these SNPs, with an additive or correlational effect, may be involved in modulating the risk of melanoma in individuals from a geographic region with a high incidence of the disease.


Asunto(s)
Biomarcadores de Tumor/genética , Melanoma/epidemiología , Polimorfismo de Nucleótido Simple , Neoplasias Cutáneas/epidemiología , Pigmentación de la Piel/genética , Antígenos de Neoplasias/genética , Antiportadores/genética , Brasil/epidemiología , Estudios de Casos y Controles , Femenino , Estudios de Seguimiento , Genotipo , Humanos , Incidencia , Masculino , Melanoma/genética , Melanoma/patología , Proteínas de Transporte de Membrana/genética , Persona de Mediana Edad , Monofenol Monooxigenasa/genética , Pronóstico , Factores de Riesgo , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Ubiquitina-Proteína Ligasas/genética
7.
Cancer Genet ; 240: 54-58, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31778928

RESUMEN

Li-Fraumeni and Li-Fraumeni-like (LFS/LFL) Syndrome are cancer predisposition syndromes caused by germline pathogenic variants in TP53 and are associated with an increased risk of multiple early-onset cancers. In Southern and Southeastern Brazil, a germline founder variant with partial penetrance located in the oligomerization domain of TP53, c.1010G>A p.(Arg337His, commonly known as R337H), has been detected in 0.3% of the general population. Recently, the functional MIR605 variant rs2043556 (A>G) has been identified as a novel LFS phenotype modifier in families with germline TP53 DNA binding variants. In this study, our goal was to verify MIR605 rs2043556 allele frequencies and further explore its possible effects on the phenotype of 238 Brazilian individuals carrying TP53 p.(Arg337His). The MIR605 rs2043556 G allele was detected in 136 (57.1%) individuals, including 25 homozygotes (10.5%), and although it had been previously associated with an earlier mean age of tumor onset, this effect was not observed in this study (p = 0.8). However, in p.(Arg337His) mutation carriers, the GG genotype was significantly associated with the occurrence of multiple primary tumors (p = 0.005). We provide further evidence of MIR605 rs2043556 G allele's effect as a phenotype modulator in carriers of germline TP53 pathogenic variants.


Asunto(s)
Predisposición Genética a la Enfermedad , Síndrome de Li-Fraumeni/genética , MicroARNs/genética , Neoplasias Primarias Múltiples/genética , Proteína p53 Supresora de Tumor/genética , Adulto , Edad de Inicio , Brasil/epidemiología , Femenino , Efecto Fundador , Mutación de Línea Germinal , Humanos , Síndrome de Li-Fraumeni/epidemiología , Masculino , Neoplasias Primarias Múltiples/epidemiología , Polimorfismo de Nucleótido Simple
8.
J Glob Oncol ; 5: 1-9, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31532708

RESUMEN

PURPOSE: Adenocarcinoma is the most common histologic subtype of non-small-cell lung cancer, representing 40% of all diagnoses. Several biomarkers are currently used to determine patient eligibility for targeted treatments, including analysis of molecular alterations in EGFR and ALK, as well as programmed death-ligand 1 (PD-L1) protein expression. Epidemiologic data reporting the frequency of these biomarkers in Brazilian patients with lung adenocarcinoma (LUAD) are limited, and existing studies predominantly included patients from the southeast region of the country. MATERIALS AND METHODS: The goal of this study was to investigate the frequency of somatic mutations in the EGFR, KRAS, NRAS, and BRAF genes, ALK, and PD-L1 expression in a series of Brazilian patients diagnosed with LUAD predominantly recruited from centers in southern Brazil. Molecular analysis of the EGFR, KRAS, NRAS, and BRAF genes was performed by next-generation sequencing using DNA extracted from tumor tissue. Immunohistochemistry was used to detect ALK and PD-L1 expression. RESULTS: Analysis of 619 tumors identified KRAS mutations in 189 (30.2%), EGFR mutations in 120 (19.16%), and BRAF mutations in 19 (3%). Immunohistochemistry demonstrated ALK and PD-L1 expression in 4% and 35.1% of patients, respectively. CONCLUSION: To our knowledge, this is the first study investigating the molecular epidemiology of patients with LUAD from southern Brazil and the largest assessing the frequency of multiple predictive biomarkers for this tumor in the country. The study also reveals a distinct mutation profile compared with data originating from other regions of Brazil.


Asunto(s)
Adenocarcinoma/diagnóstico , Biomarcadores/química , Neoplasias Pulmonares/diagnóstico , Adenocarcinoma/patología , Brasil , Humanos , Neoplasias Pulmonares/patología , Estudios Retrospectivos
9.
Sci Rep ; 9(1): 11413, 2019 08 06.
Artículo en Inglés | MEDLINE | ID: mdl-31388035

RESUMEN

Thalidomide is widely used for several diseases; however, it causes malformations in embryos exposed during pregnancy. The complete understanding of the mechanisms by which thalidomide affects the embryo development has not yet been obtained. The phenotypic similarity makes TE a phenocopy of syndromes caused by mutations in ESCO2, SALL4 and TBX5 genes. Recently, SALL4 and TBX5 were demonstrated to be thalidomide targets. To understand if these genes act in the TE development, we sequenced them in 27 individuals with TE; we verified how thalidomide affect them in human pluripotent stem cells (hPSCs) through a differential gene expression (DGE) analysis from GSE63935; and we evaluated how these genes are functionally related through an interaction network analysis. We identified 8 variants in ESCO2, 15 in SALL4 and 15 in TBX5. We compared allelic frequencies with data from ExAC, 1000 Genomes and ABraOM databases; eight variants were significantly different (p < 0.05). Eleven variants in SALL4 and TBX5 were previously associated with cardiac diseases or malformations; however, in TE sample there was no association. Variant effect prediction tools showed 97% of the variants with potential to influence in these genes regulation. DGE analysis showed a significant reduction of ESCO2 in hPSCs after thalidomide exposure.


Asunto(s)
Acetiltransferasas/genética , Proteínas Cromosómicas no Histona/genética , Predisposición Genética a la Enfermedad , Proteínas de Dominio T Box/genética , Teratogénesis/genética , Talidomida/efectos adversos , Factores de Transcripción/genética , Anomalías Múltiples/inducido químicamente , Anomalías Múltiples/genética , Brasil , Línea Celular , Anomalías Craneofaciales/inducido químicamente , Anomalías Craneofaciales/genética , Conjuntos de Datos como Asunto , Síndrome de Retracción de Duane/inducido químicamente , Síndrome de Retracción de Duane/genética , Ectromelia/inducido químicamente , Ectromelia/genética , Femenino , Perfilación de la Expresión Génica , Frecuencia de los Genes , Cardiopatías Congénitas/inducido químicamente , Cardiopatías Congénitas/genética , Defectos del Tabique Interatrial/inducido químicamente , Defectos del Tabique Interatrial/genética , Humanos , Hipertelorismo/inducido químicamente , Hipertelorismo/genética , Lepra/tratamiento farmacológico , Deformidades Congénitas de las Extremidades Inferiores/inducido químicamente , Deformidades Congénitas de las Extremidades Inferiores/genética , Masculino , Mutación , Células Madre Pluripotentes , Polimorfismo de Nucleótido Simple , Embarazo , Complicaciones del Embarazo/tratamiento farmacológico , Mapas de Interacción de Proteínas/genética , Teratogénesis/efectos de los fármacos , Deformidades Congénitas de las Extremidades Superiores/inducido químicamente , Deformidades Congénitas de las Extremidades Superiores/genética
10.
Fam Cancer ; 18(4): 451-456, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31321604

RESUMEN

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.


Asunto(s)
Asesoramiento Genético , Síndrome de Li-Fraumeni/genética , Proteína p53 Supresora de Tumor/genética , Adulto , Anciano , Femenino , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Masculino , Persona de Mediana Edad
11.
Genet Mol Biol ; 42(1 suppl 1): 215-231, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31067289

RESUMEN

Germline mutations in BRCA1 and BRCA2 (BRCA) genes confer high risk of developing cancer, especially breast and ovarian tumors. Since the cloning of these tumor suppressor genes over two decades ago, a significant amount of research has been done. Most recently, monoallelic loss-of-function mutations in PALB2 have also been shown to increase the risk of breast cancer. The identification of BRCA1, BRCA2 and PALB2 as proteins involved in DNA double-strand break repair by homologous recombination and of the impact of complete loss of BRCA1 or BRCA2 within tumors have allowed the development of novel therapeutic approaches for patients with germline or somatic mutations in said genes. Despite the advances, especially in the clinical use of PARP inhibitors, key gaps remain. Now, new roles for BRCA1 and BRCA2 are emerging and old concepts, such as the classical two-hit hypothesis for tumor suppression, have been questioned, at least for some BRCA functions. Here aspects regarding cancer predisposition, cellular functions, histological and genomic findings in BRCA and PALB2-related tumors will be presented, in addition to an up-to-date review of the evolution and challenges in the development and clinical use of PARP inhibitors.

12.
Fam Cancer ; 17(2): 269-274, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-28756477

RESUMEN

Li-Fraumeni and Li-Fraumeni-like syndrome (LFS/LFL) are clinically heterogeneous cancer predisposition syndromes characterized by diagnosis of early-onset and often multiple cancers with variable tumor patterns and incomplete penetrance. To date, the genetic modifiers described in LFS/LFL have been shown to map to either TP53 or its main negative regulator, MDM2. Additionally, all studies were focused on families with different TP53 germline mutations. Hence, in this study we explored the effect of the most studied polymorphisms of p53 pathway genes on clinical manifestations of individuals carrying the founder TP53 mutation R337H (n = 136) and controls (n = 186). Cancer-affected carriers had been diagnosed either with adrenocortical carcinoma (ACC, n = 29) or breast cancer (BC, n = 43). Allelic discrimation using TaqMan assay was used for genotyping MDM2 SNP 309 (rs2279744) as well as MDM4 (rs1563828) and USP7 (rs1529916) polymorphisms. We found significantly higher MDM2 SNP 309 GG genotype and G allele frequencies in the LFS cohort than in controls. Furthermore, median age at first diagnosis was earlier in MDM2 SNP309 GG carriers when compared to other genotypes for both cancers (ACC: age 1 vs. 2 years; BC: age 35 vs. 43 years, respectively), although not statistically different. The allelic and genotypic frequencies for all SNPs did not differ between cancer affected and unaffected carriers, neither between patients with ACC or BC. In conclusion, our results suggest that MDM2 SNP 309 may contribute to the LFL phenotype and also to an earlier age at diagnosis of ACC and BC cancer in carriers of the R337H founder mutation.


Asunto(s)
Predisposición Genética a la Enfermedad , Síndrome de Li-Fraumeni/genética , Proteínas Proto-Oncogénicas c-mdm2/genética , Transducción de Señal/genética , Proteína p53 Supresora de Tumor/metabolismo , Neoplasias de la Corteza Suprarrenal/genética , Neoplasias de la Corteza Suprarrenal/patología , Carcinoma Corticosuprarrenal/genética , Carcinoma Corticosuprarrenal/patología , Adulto , Edad de Inicio , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Frecuencia de los Genes , Humanos , Lactante , Síndrome de Li-Fraumeni/patología , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , Proteína p53 Supresora de Tumor/genética
13.
Genet Mol Biol ; 39(2): 203-9, 2016 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-27275664

RESUMEN

Germline mutations in the TP53 gene are associated with Li-Fraumeni and Li-Fraumeni-Like Syndromes, characterized by increased predisposition to early-onset cancers. In Brazil, the prevalence of the TP53-p.R337H germline mutation is exceedingly high in the general population and in cancer-affected patients, probably as result of a founder effect. Several genotyping methods are used for the molecular diagnosis of LFS/LFL, however Sanger sequencing is still considered the gold standard. We compared performance, cost and turnaround time of Sanger sequencing, PCR-RFLP, TaqMan-PCR and HRM in the p.R337H genotyping. The performance was determined by analysis of 95 genomic DNA samples and results were 100% concordant for all methods. Sequencing was the most expensive method followed by TaqMan-PCR, PCR-RFLP and HRM. The overall cost of HRM increased with the prevalence of positive samples, since confirmatory sequencing must be performed when a sample shows an abnormal melting profile, but remained lower than all other methods when the mutation prevalence was less than 2.5%. Sequencing had the highest throughput and the longest turnaround time, while TaqMan-PCR showed the lowest turnaround and hands-on times. All methodologies studied are suitable for the detection of p.R337H and the choice will depend on the application and clinical scenario.

14.
PLoS One ; 7(10): e47010, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23056559

RESUMEN

Germline mutations in TP53 are the underlying defect of Li-Fraumeni Syndrome (LFS) and Li-Fraumeni-like (LFL) Syndrome, autosomal dominant disorders characterized by predisposition to multiple early onset cancers. In Brazil, a variant form of LFS/LFL is commonly detected because of the high prevalence of a founder mutation at codon 337 in TP53 (p.R337H). The p53 protein exerts multiple roles in the regulation of oxidative metabolism and cellular anti-oxidant defense systems. Herein, we analyzed the redox parameters in blood samples from p.R337H mutation carriers (C, n = 17) and non-carriers (NC, n = 17). We identified a significant increase in erythrocyte GPx activity and in plasma carbonyl content,an indicator of protein oxidative damage, in mutation carriers compared to non-carriers (P = 0.048 and P = 0.035, respectively). Mutation carriers also showed a four-fold increase in plasma malondialdehyde levels, indicating increased lipid peroxidation (NC = 40.20±0.71, C = 160.5±0.88, P<0.0001). Finally, carriers showed increased total antioxidant status but a decrease in plasma ascorbic acid content. The observed imbalance could be associated with deregulated cell bioenergetics and/or with increased inflammatory stress, two effects that may result from loss of wild-type p53 function. These findings provide the first evidence that oxidative damage occurs in carriers of a germline TP53 mutation, and these may have important implications regarding our understanding of the mechanisms responsible for germline TP53 p.R337H mutation-associated carcinogenesis.


Asunto(s)
Codón/genética , Mutación de Línea Germinal , Heterocigoto , Estrés Oxidativo/genética , Proteína p53 Supresora de Tumor/genética , Adolescente , Adulto , Antioxidantes/metabolismo , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Malondialdehído/sangre , Persona de Mediana Edad , Adulto Joven
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