Biomarcadores no câncer de mama e ovário : uma correlação entre alterações genéticas e aspectos histopatológicos

• Autor(a) principal: Wolfgramm, Eldamária de Vargas
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/4511
• topic: Breast cancer; Ovarian cancer; Epidemiology; Molecular study; Câncer de mama; Câncer de ovário; Epidemiologia; Estudo molecular; Marcadores do tipo STR; SNP; Espírito Santo; STR markers; Biotecnologia; 61

Breast and ovarian cancers are hormone-related diseases and polymorphisms in cancer genetic susceptibility genes involved in the production and metabolism of steroid hormones play an important role in the carcinogenesis of these tumors. Particularly, polymorphisms in short tandem repeat regions (STR) provide information about two events: microsatellite instability (MSI) and loss of heterozygosis (LOH). To check the presence of MSI and LOH in breast and ovarian cancers, 12 STR markers (CYP11, CYP19, UGT1A1, AR, ERα, ERβ, D5S345, D17S250, D10S197, D8S135, D3S1611 and D2S119) were analyzed in this study by Polymerase Chain Reaction (PCR) in 107 breast and 24 ovarian tumors. Single nucleotide polymorphisms (SNPs) in GSTP1 (A313G) and CYP17 (T27C) genes were also analyzed to estimate the frequency of susceptibility gene polymorphisms. In addition to the molecular analysis, an epidemiological study was conducted through the analysis of two oncology reference Hospital Pathology Service records in Espirito Santo, Brazil, during years 2001 to 2004 and 2009 to 2010. The epidemiological study detected 1,758 malignant breast and 119 ovarian tumors. Mean ages for malignant breast and ovarian tumors were 53.59 and 52.98 years, respectively. Among breast tumors, infiltrating ductal carcinoma was the most frequent malignant tumor and an increased tumor frequency in age group ≤ 35 years was observed for other malignant tumors of the breast in the time period 2009-2010, as compared to time period 2001-2004. The molecular study has shown that LOH is an event more frequently observed that MSI, in both breast and ovarian cancers. In breast carcinomas, the combination of STR markers showed that AR, CYP19 and ERβ, when analyzed together, were correlated with parameters of histological grade III, ER (estrogen receptor) negative tumors and PR (progesterone receptor) negative tumors. The combination of markers did not show significant results in ovarian tumors. Combination between STR markers and GSTP1 and CYP17 genotypes were performed, showing positive correlations among GSTP1 Ile/Ile genotype, AR+CYP19 (p=0.021) and AR+ERβ+CYP19 (p=0.036) alteration in PR negatives breast cancers, while CYP17 A1/A1 genotype was associated with AR+ERβ and AR+ERβ+CYP19 alterations in ER and PR negative breast tumors (p=0.039 to all combinations). We did not find associations between gene combinations and ovarian tumors. These data support the hypothesis that genes related to steroid metabolism are important in the characterization of breast cancer and that the analysis of a single polymorphism may not be enough to molecular characterize a tumor.