RESUMEN
Purpose: Pathogenic POLE proofreading domain mutations are found in many malignancies where they are associated with ultramutation and favorable prognosis. The extent to which this prognosis depends on their sensitivity to adjuvant treatment is unknown, as is the optimal therapy for advanced-staged or recurrent POLE-mutant cancers.Experimental Design: We examined the recurrence-free survival of women with POLE-mutant and POLE-wild-type endometrial cancers (EC) in the observation arm of the randomized PORTEC-1 endometrial cancer trial (N = 245 patients with stage I endometrial cancer for analysis). Sensitivity to radiotherapy and selected chemotherapeutics was compared between Pole-mutant mouse-derived embryonic stem (mES) cells, generated using CRISPR-Cas9 (Pole mutations D275A/E275A, and cancer-associated P286R, S297F, V411L) and isogenic wild-type cell lines.Results: In the observation arm of the PORTEC-1 trial (N = 245), women with POLE-mutant endometrial cancers (N = 16) had an improved recurrence-free survival (10-year recurrence-free survival 100% vs. 80.1% for POLE-wild-type; HR, 0.143; 95% confidence interval, 0.001-0.996; P = 0.049). Pole mutations did not increase sensitivity to radiotherapy nor to chemotherapeutics in mES cells. In contrast, Pole-mutant cells displayed significantly increased sensitivity to cytarabine and fludarabine (IC50Pole P286R-mutant vs. wild-type: 0.05 vs. 0.17 µmol/L for cytarabine, 4.62 vs. 11.1 µmol/L for fludarabine; P < 0.001 for both comparisons).Conclusions: The favorable prognosis of POLE-mutant cancers cannot be explained by increased sensitivity to currently used adjuvant treatments. These results support studies exploring minimization of adjuvant therapy for early-stage POLE-mutant cancers, including endometrial and colorectal cancers. Conversely, POLE mutations result in hypersensitivity to nucleoside analogues, suggesting the use of these compounds as a potentially effective targeted treatment for advanced-stage POLE-mutant cancers. Clin Cancer Res; 24(13); 3197-203. ©2018 AACR.
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Biomarcadores de Tumor , ADN Polimerasa II/genética , Resistencia a Antineoplásicos/genética , Mutación , Neoplasias/genética , Proteínas de Unión a Poli-ADP-Ribosa/genética , Dominios y Motivos de Interacción de Proteínas/genética , Tolerancia a Radiación/genética , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Quimioterapia Adyuvante , ADN Polimerasa II/química , Femenino , Humanos , Masculino , Estadificación de Neoplasias , Neoplasias/mortalidad , Neoplasias/patología , Neoplasias/terapia , Proteínas de Unión a Poli-ADP-Ribosa/química , Pronóstico , Radioterapia Adyuvante , Resultado del TratamientoRESUMEN
Purpose: Molecular classification of endometrial cancer identified distinct molecular subgroups. However, the largest subset of endometrial cancers remains poorly characterized and is referred to as the "nonspecific molecular profile" (NSMP) subgroup. Here, we aimed at refining the classification of this subgroup by profiling somatic copy-number aberrations (SCNAs).Experimental Design: SCNAs were analyzed in 141 endometrial cancers using whole-genome SNP arrays and pooled with 361 endometrial cancers from The Cancer Genome Atlas. Genomic Identification of Significant Targets in Cancer (GISTIC) identified statistically enriched SCNAs and penalized Cox regression assessed survival effects. The prognostic significance of relevant SCNAs was validated using multiplex ligation-dependent probe amplification in 840 endometrial cancers from the PORTEC-1/2 trials. Copy-number status of genes was correlated with gene expression to identify potential cancer drivers. One plausible oncogene was validated in vitro using antisense oligonucleotide-based strategy.Results: SCNAs affecting chromosome 1q32.1 significantly correlated with worse relapse-free survival (RFS) in the NSMP subgroup (HR, 2.12; 95% CI, 1.26-3.59; P = 0.005). This effect was replicated in NSMP endometrial cancers from PORTEC-1/2 (HR, 2.34; 95% CI, 1.17-4.70; P = 0.017). A new molecular classification including the 1q32.1 amplification improved risk prediction of recurrence. MDM4 gene expression strongly correlated with 1q32.1 amplification. Silencing MDM4 inhibited cell growth in cell lines carrying 1q32.1 amplification, but not in those without MDM4 amplification. Vice versa, increasing MDM4 expression in nonamplified cell lines stimulated cell proliferation.Conclusions: 1q32.1 amplification was identified as a prognostic marker for poorly characterized NSMP endometrial cancers, refining the molecular classification of this subgroup. We functionally validated MDM4 as a potential oncogenic driver in the 1q32.1 region. Clin Cancer Res; 23(23); 7232-41. ©2017 AACR.
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Cromosomas Humanos Par 1/genética , Variaciones en el Número de Copia de ADN/genética , Neoplasias Endometriales/genética , Amplificación de Genes , Anciano , Línea Celular Tumoral , Análisis por Conglomerados , Supervivencia sin Enfermedad , Neoplasias Endometriales/patología , Neoplasias Endometriales/terapia , Femenino , Perfilación de la Expresión Génica/métodos , Humanos , Persona de Mediana Edad , Recurrencia Local de Neoplasia , Evaluación de Resultado en la Atención de Salud/métodos , Evaluación de Resultado en la Atención de Salud/estadística & datos numéricos , Pronóstico , Modelos de Riesgos ProporcionalesRESUMEN
JAK1 frameshift mutations may promote cancer cell immune evasion by impeding upregulation of the antigen presentation pathway in microsatellite unstable endometrial cancers (ECs). This study investigated the JAK1 mutation frequency, its functional implication in immune evasion and its prognostic significance in microsatellite unstable EC. Microsatellite instability and three microsatellite repeats within JAK1 were analyzed in 181 ECs. Sixty-two (34%) ECs showed microsatellite instability, of which 22 (35%) had a JAK1 mutation. LMP7, TAP1 and HLA class I protein expression and the presence of CD8-positive T-cells were analyzed in the microsatellite unstable ECs. JAK1 mutant microsatellite unstable ECs showed impaired upregulation of LMP7 (P=0.074) and HLA class I (P<0.001), validated using RNAseq data of the TCGA. TAP1 expression and presence of CD8-positive T-cells were not related to JAK1 mutations. In 198 additional microsatellite unstable ECs, the JAK1 mutation frequency was confirmed but no prognostic significance was found. For, JAK1 wildtype (n=135, 72%) and mutant (n=52, 28%) ECs, 10-year recurrence free rates were 84% and 77% (P=0.301). These observations show that JAK1 mutations are highly frequent in microsatellite unstable EC, not associated with survival, but are associated with impaired upregulation of LMP7 and HLA class I and may therefore facilitate immune escape.
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Neoplasias Endometriales/genética , Mutación del Sistema de Lectura , Janus Quinasa 1/genética , Inestabilidad de Microsatélites , Anciano , Presentación de Antígeno , Estudios de Cohortes , Metilación de ADN , Análisis Mutacional de ADN , ADN de Neoplasias , Neoplasias Endometriales/metabolismo , Femenino , Antígenos de Histocompatibilidad Clase I/metabolismo , Humanos , Repeticiones de Microsatélite , Persona de Mediana Edad , Recurrencia Local de Neoplasia/genética , Pronóstico , Complejo de la Endopetidasa Proteasomal/metabolismo , Análisis de Secuencia de ARNRESUMEN
PURPOSE: Recommendations for adjuvant treatment for women with early-stage endometrial carcinoma are based on clinicopathologic features. Comprehensive genomic characterization defined four subgroups: p53-mutant, microsatellite instability (MSI), POLE-mutant, and no specific molecular profile (NSMP). We aimed to confirm the prognostic capacity of these subgroups in large randomized trial populations, investigate potential other prognostic classifiers, and integrate these into an integrated molecular risk assessment guiding adjuvant therapy. EXPERIMENTAL DESIGN: Analysis of MSI, hotspot mutations in 14 genes including POLE, protein expression of p53, ARID1a, ß-catenin, L1CAM, PTEN, ER, and PR was undertaken on 947 available early-stage endometrioid endometrial carcinomas from the PORTEC-1 and -2 trials, mostly high-intermediate risk (n = 614). Prognostic value was determined using univariable and multivariable Cox proportional hazard models. AUCs of different risk stratification models were compared. RESULTS: Molecular analyses were feasible in >96% of the patients and confirmed the four molecular subgroups: p53-mutant (9%), MSI (26%), POLE-mutant (6%), and NSMP (59%). Integration of prognostic molecular alterations with established clinicopathologic factors resulted in a stronger model with improved risk prognostication. Approximately 15% of high-intermediate risk patients had unfavorable features (substantial lymphovascular space invasion, p53-mutant, and/or >10% L1CAM), 50% favorable features (POLE-mutant, NSMP being microsatellite stable, and CTNNB1 wild-type), and 35% intermediate features (MSI or CTNNB1-mutant). CONCLUSIONS: Integrating clinicopathologic and molecular factors improves the risk assessment of patients with early-stage endometrial carcinoma. Assessment of this integrated risk profile is feasible in daily practice, and holds promise to reduce both overtreatment and undertreatment. Clin Cancer Res; 22(16); 4215-24. ©2016 AACR.
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Biomarcadores de Tumor , Neoplasias Endometriales/diagnóstico , Neoplasias Endometriales/genética , Adulto , Anciano , Anciano de 80 o más Años , Área Bajo la Curva , ADN Polimerasa II/genética , Neoplasias Endometriales/mortalidad , Neoplasias Endometriales/terapia , Femenino , Genes p53 , Humanos , Persona de Mediana Edad , Mutación , Clasificación del Tumor , Estadificación de Neoplasias , Proteínas de Unión a Poli-ADP-Ribosa/genética , Pronóstico , Ensayos Clínicos Controlados Aleatorios como Asunto , Recurrencia , Medición de Riesgo , Análisis de SupervivenciaRESUMEN
OBJECTIVE: The standard treatment of early-stage (FIGO [International Federation of Gynecology and Obstetrics] I) endometrioid endometrial cancer (EEC) is hysterectomy with bilateral salpingo-oophorectomy. An alternative approach for younger women with low-grade EEC who wish to preserve fertility may be hormonal treatment. Previous studies have suggested that progesterone may elicit its antitumor effect in EEC by interacting with the Wingless (Wnt) and/or phosphatidylinositol 3-kinase (PI3K)/Akt pathways. Therefore, we explored whether common activating genetic alterations in Wnt and PI3K/Akt signaling correlated with nonresponsiveness to progesterone therapy for low-grade EEC. In addition, we investigated whether benign morphology under progesterone treatment is accompanied by the absence of genetic changes. METHODS: We analyzed molecular alterations in the Wnt and PI3K/Akt signaling in 84 serial endometrial samples from 11 premenopausal patients with progesterone receptor-positive low-grade EEC conservatively treated with progesterone and correlated these with histological and clinical follow-up. RESULTS: There were 6 responders and 5 nonresponders to progesterone treatment. The response rate to progesterone treatment was 55%, and the relapse rate was 83%. All responders had alterations in both the Wnt and PI3K/Akt pathway before treatment. In the nonresponder group, tumors inconsistently showed alterations in none, 1, or both pathways. Normalization of the endometrium morphology under progesterone treatment is accompanied by the absence of the genetic changes found in the specimen before treatment. CONCLUSIONS: We found that activating molecular alterations in either Wnt or PI3K/Akt signaling pathways did not predict resistance to progesterone treatment. It seems that morphological response goes along with disappearance of the established mutations. This exploratory study suggests that Wnt or PI3K/Akt status is unable to predict response to progesterone treatment in patients with EEC.
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Biomarcadores de Tumor/metabolismo , Neoplasias Endometriales/metabolismo , Neoplasias Endometriales/patología , Preservación de la Fertilidad , Fosfatidilinositol 3-Quinasas/metabolismo , Progesterona/uso terapéutico , Proteínas Proto-Oncogénicas c-akt/metabolismo , Adulto , Neoplasias Endometriales/tratamiento farmacológico , Femenino , Estudios de Seguimiento , Humanos , Técnicas para Inmunoenzimas , Estadificación de Neoplasias , Progestinas/uso terapéutico , Pronóstico , Estudios Retrospectivos , Transducción de SeñalRESUMEN
Cervical cancer is typically well infiltrated by immune cells. Because of the intricate relationship between cancer cells and immune cells, we aimed to identify both cancer cell and immune cell expressed biomarkers. Using a novel approach, we isolated RNA from flow-sorted viable EpCAM+ tumor epithelial cells and CD45+ tumor-infiltrating immune cells obtained from squamous cell cervical cancer samples (n = 24). Total RNA was sequenced and differential gene expression analysis of the CD45+ immune cell fractions identified TCL1A as a novel marker for predicting improved survival (p = 0.007). This finding was validated using qRT-PCR (p = 0.005) and partially validated using immunohistochemistry (p = 0.083). Importantly, TCL1A was found to be expressed in a subpopulation of B cells (CD3-/CD19+/CD10+/CD34-) using multicolor immunofluorescence. A high TCL1A/CD20 (B cell) ratio, determined in total tumor samples from a separate patient cohort using qRT-PCR (n = 52), was also correlated with improved survival (p = 0.027). This is the first study demonstrating the prognostic value of separating tumor epithelial cells from tumor-infiltrating immune cells and determining their RNA expression profile for identifying putative cancer biomarkers. Our results suggest that intratumoral TCL1A+ B cells are important for controlling cervical cancer development.
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Linfocitos B/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Neoplasias del Cuello Uterino/genética , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Perfilación de la Expresión Génica , Humanos , Persona de Mediana Edad , Pronóstico , Análisis de Supervivencia , Microambiente Tumoral , Neoplasias del Cuello Uterino/mortalidad , Neoplasias del Cuello Uterino/patologíaRESUMEN
BACKGROUND: The tumour microenvironment comprises a network of immune response and vascularization factors. From this network, we identified immunological and vascularization gene expression clusters and the correlations between the clusters. We subsequently determined which factors were correlated with patient survival in cervical carcinoma. METHODS: The expression of 42 genes was investigated in 52 fresh frozen squamous cervical cancer samples by qRT-PCR. Weighted gene co-expression network analysis and mixed-model analyses were performed to identify gene expression clusters. Correlations and survival analyses were further studied at expression cluster and single gene level. RESULTS: We identified four immune response clusters: 'T cells' (CD3E/CD8A/TBX21/IFNG/FOXP3/IDO1), 'Macrophages' (CD4/CD14/CD163), 'Th2' (IL4/IL5/IL13/IL12) and 'Inflammation' (IL6/IL1B/IL8/IL23/IL10/ARG1) and two vascularization clusters: 'Angiogenesis' (VEGFA/FLT1/ANGPT2/ PGF/ICAM1) and 'Vessel maturation' (PECAM1/VCAM1/ANGPT1/SELE/KDR/LGALS9). The 'T cells' module was correlated with all modules except for 'Inflammation', while 'Inflammation' was most significantly correlated with 'Angiogenesis' (p < 0.001). High expression of the 'T cells' cluster was correlated with earlier TNM stage (p = 0.007). High CD3E expression was correlated with improved disease-specific survival (p = 0.022), while high VEGFA expression was correlated with poor disease-specific survival (p = 0.032). Independent predictors of poor disease-specific survival were IL6 (hazard ratio = 2.3, p = 0.011) and a high IL6/IL17 ratio combined with low IL5 expression (hazard ratio = 4.2, p = 0.010). CONCLUSIONS: 'Inflammation' marker IL6, especially in combination with low levels of IL5 and IL17, was correlated with poor survival. This suggests that IL6 promotes tumour growth, which may be suppressed by a Th17 and Th2 response. Measuring IL6, IL5 and IL17 expression may improve the accuracy of predicting prognosis in cervical cancer.
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Carcinoma de Células Escamosas/inmunología , Expresión Génica/inmunología , Neovascularización Patológica/inmunología , Neoplasias del Cuello Uterino/inmunología , Adulto , Anciano , Femenino , Humanos , Inflamación/inmunología , Linfocitos Infiltrantes de Tumor/inmunología , Macrófagos/inmunología , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Análisis de Supervivencia , Linfocitos T Reguladores/inmunología , Microambiente Tumoral/inmunología , Adulto JovenRESUMEN
PURPOSE: Recent studies have shown that 7% to 12% of endometrial cancers are ultramutated due to somatic mutation in the proofreading exonuclease domain of the DNA replicase POLE. Interestingly, these tumors have an excellent prognosis. In view of the emerging data linking mutation burden, immune response, and clinical outcome in cancer, we investigated whether POLE-mutant endometrial cancers showed evidence of increased immunogenicity. EXPERIMENTAL DESIGN: We examined immune infiltration and activation according to tumor POLE proofreading mutation in a molecularly defined endometrial cancer cohort including 47 POLE-mutant tumors. We sought to confirm our results by analysis of RNAseq data from the TCGA endometrial cancer series and used the same series to examine whether differences in immune infiltration could be explained by an enrichment of immunogenic neoepitopes in POLE-mutant endometrial cancers. RESULTS: Compared with other endometrial cancers, POLE mutants displayed an enhanced cytotoxic T-cell response, evidenced by increased numbers of CD8(+) tumor-infiltrating lymphocytes and CD8A expression, enrichment for a tumor-infiltrating T-cell gene signature, and strong upregulation of the T-cell cytotoxic differentiation and effector markers T-bet, Eomes, IFNG, PRF, and granzyme B. This was accompanied by upregulation of T-cell exhaustion markers, consistent with chronic antigen exposure. In silico analysis confirmed that POLE-mutant cancers are predicted to display more antigenic neoepitopes than other endometrial cancers, providing a potential explanation for our findings. CONCLUSIONS: Ultramutated POLE proofreading-mutant endometrial cancers are characterized by a robust intratumoral T-cell response, which correlates with, and may be caused by an enrichment of antigenic neopeptides. Our study provides a plausible mechanism for the excellent prognosis of these cancers.
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ADN Polimerasa II/genética , Neoplasias Endometriales/genética , Neoplasias Endometriales/inmunología , Mutación , Estudios de Cohortes , Análisis Mutacional de ADN , ADN Polimerasa II/inmunología , Femenino , Técnica del Anticuerpo Fluorescente , Humanos , Inmunohistoquímica , Linfocitos Infiltrantes de Tumor/inmunología , Proteínas de Unión a Poli-ADP-Ribosa , Reacción en Cadena de la PolimerasaRESUMEN
Genetic variation of antigen-processing machinery (APM) components has been shown to be associated with cervical carcinoma risk and outcome in a genetically homogeneous Dutch population. However, the role of APM component single nucleotide polymorphisms (SNPs) in genetically heterogeneous populations with different distributions of human papillomavirus (HPV) subtypes remains unclear. Eleven non-synonymous, coding SNPs in the TAP1, TAP2, LMP2, LMP7 and ERAP1 genes were genotyped in cervical carcinoma patients and healthy controls from two distinct Indonesian populations (Balinese and Javanese). Individual genotype and allele distributions were investigated using single-marker analysis, and combined SNP effects were assessed by haplotype construction and haplotype interaction analysis. Allele distribution patterns in Bali and Java differed in relation to cervical carcinoma risk, with four ERAP1 SNPs and one TAP2 SNP in the Javanese population showing significant association with cervical carcinoma risk, while in the Balinese population, only one TAP2 SNP showed this association. Multimarker analysis demonstrated that in the Javanese patients, one specific haplotype, consisting of the ERAP1-575 locus on chromosome 5 and the TAP2-379 and TAP2-651 loci on chromosome 6, was significantly associated with cervical carcinoma risk (global P = 0.008); no significant haplotype associations were found in the Balinese population. These data indicate not only that genetic variation in APM component genes is associated with cervical carcinoma risk in Indonesia but also that the patterns of association differ depending on background genetic composition and possibly on differences in HPV type distribution.
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Presentación de Antígeno/genética , Carcinoma/genética , Genética de Población , Neoplasias del Cuello Uterino/genética , Alelos , Presentación de Antígeno/inmunología , Carcinoma/inmunología , Carcinoma/patología , Femenino , Predisposición Genética a la Enfermedad , Variación Genética , Haplotipos , Humanos , Indonesia , Polimorfismo de Nucleótido Simple , Factores de Riesgo , Neoplasias del Cuello Uterino/inmunología , Neoplasias del Cuello Uterino/patologíaRESUMEN
BACKGROUND: Two etiologic pathways of vulvar cancer are known, a human papillomavirus (HPV)- and a TP53-associated route, respectively, but other genetic changes may also play a role. Studies on somatic mutations in vulvar cancer other than TP53 are limited in number and size. In this study, we investigated the prevalence of genetic mutations in 107 vulvar squamous cell carcinomas (VSCCs). METHODS: A total of 107 paraffin-embedded tissue samples of primarily surgically treated VSCCs were tested for HPV infection and screened for mutations in 14 genes (BRAF, CDKN2A(p16), CTNNB1, FBXW7, FGFR2, FGFR3, FOXL2, HRAS, KRAS, NRAS, PIK3CA, PPP2R1A, PTEN, and TP53) using Sanger sequencing and mass spectrometry. RESULTS: Mutations were detected in 7 genes. Of 107 VSCCs, 66 tumors (62%) contained at least one mutation (TP53=58, CDKN2A(p16)=14, HRAS=10, PIK3CA=7, PPP2R1A=3, KRAS=1, PTEN=1). Mutations occurred most frequently in HPV-negative samples. Five-year survival was significantly worse for patients with a mutation (47% vs 59%, P=.035), with a large effect from patients carrying HRAS-mutations. CONCLUSION: Somatic mutations were detected in 62% of VSCCs. As expected, HPV infection and TP53-mutations play a key role in the development of VSCC, but CDKN2A(p16), HRAS, and PIK3CA-mutations were also frequently seen in HPV-negative patients. Patients with somatic mutations, especially HRAS-mutations, have a significantly worse prognosis than patients lacking these changes, which could be of importance for the development of targeted therapy.
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Carcinoma de Células Escamosas/genética , Genes p16 , Mutación , Proteínas Proto-Oncogénicas p21(ras)/genética , Neoplasias de la Vulva/genética , Anciano , Carcinoma de Células Escamosas/mortalidad , Inhibidor p16 de la Quinasa Dependiente de Ciclina , Femenino , Humanos , Proteínas de Neoplasias , Tasa de Supervivencia , Neoplasias de la Vulva/mortalidadRESUMEN
Somatic mutations play a major role in tumour initiation and progression. The mutation status of a tumour may predict prognosis and guide targeted therapies. The majority of techniques to study oncogenic mutations require high quality and quantity DNA or are analytically challenging. Mass-spectrometry based mutation analysis however is a relatively simple and high-throughput method suitable for formalin-fixed, paraffin-embedded (FFPE) tumour material. Targeted gene panels using this technique have been developed for several types of cancer. These current cancer hotspot panels are not focussed on the genes that are most relevant in gynaecological cancers. In this study, we report the design and validation of a novel, mass-spectrometry based panel specifically for gynaecological malignancies and present the frequencies of detected mutations. Using frequency data from the online Catalogue of Somatic Mutations in Cancer, we selected 171 somatic hotspot mutations in the 13 most important genes for gynaecological cancers, being BRAF, CDKN2A, CTNNB1, FBXW7, FGFR2, FGFR3, FOXL2, HRAS, KRAS, NRAS, PIK3CA, PPP2R1A and PTEN. A total of 546 tumours (205 cervical, 227 endometrial, 89 ovarian, and 25 vulvar carcinomas) were used to test and validate our panel, and to study the prevalence and spectrum of somatic mutations in these types of cancer. The results were validated by testing duplicate samples and by allele-specific qPCR. The panel presented here using mass-spectrometry shows to be reproducible and high-throughput, and is usefull in FFPE material of low quality and quantity. It provides new possibilities for studying large numbers of gynaecological tumour samples in daily practice, and could be useful in guided therapy selection.
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Análisis Mutacional de ADN/métodos , Neoplasias de los Genitales Femeninos/genética , Femenino , Genes Relacionados con las Neoplasias , Humanos , Reacción en Cadena de la Polimerasa Multiplex , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
The capacity of a low-dose HPV16 synthetic long-peptide vaccine (HPV16-SLP) to induce an HPV16-specific T-cell response as well as to establish long-term immunologic memory in patients with low-grade abnormalities of the cervix was determined in a placebo-controlled, double-blinded phase II study. In addition, the effect of a booster vaccination after 1 year was evaluated. Patients received either the HPV16-SLP or a placebo at the start of the study. After 1 year, the vaccinated patients were again randomized to receive the HPV16-SLP or a placebo. Patients were followed for 2 years. HPV16-specific T-cell responses were determined in pre- and post-vaccination blood samples by ELISPOT, proliferation assay and cytokine assays. We show that the HPV16-specific T-cell responses detected after vaccination are clearly due to vaccination and that reactivity was maintained for at least 2 years. Interestingly, a booster vaccination after 1 year especially augmented the HPV16-specific Th2 response. Furthermore, pre-existing immunity to HPV16 was associated with a stronger response to vaccination and with more side effects, reflected by flu-like symptoms. We conclude that two low-dose injections of HPV16-SLP can induce a strong and stable HPV16-specific T-cell response that lasts for at least 1 year. If booster vaccination is required, then polarizing adjuvant should be added to maintain the Th1 focus of the vaccine-induced T-cell response.