Steroid metabolism gene polymorphisms and their implications on breast and ovarian cancer prognosis.

A role for estrogen in the etiology of breast and ovarian cancers has been suggested; therefore, genetic polymorphisms in steroid metabolism genes could be involved in the carcinogenesis of these tumors. We have aimed to investigate the role of GSTP1 and CYP17 polymorphisms and their correlation with MSI (microsatellite instability) and LOH (loss of heterozygosity) in AR, ERß and CYP19 genes in women from Espírito Santo State, Brazil. The study population consisted of 107 female breast and 24 ovarian tumors. GSTP1 and CYP17 polymorphisms were detected by polymerase chain reaction (PCR) amplification followed by restriction fragment length polymorphism (RFLP) analysis while MSI and LOH were analyzed by PCR. GSTP1 and CYP17 polymorphisms alone were not associated with an increased risk for breast or ovarian tumors. However, when combined with MSI/LOH in AR, ERß and CYP19 genes, we were able to detect significant associations with the GSTP1 wild-type genotype in PR (progesterone receptor) negative breast cancers or the CYP17 wild-type genotype in ER (estrogen receptor) and PR-negative breast tumors. No associations with ovarian tumors were detected. Our results suggest that wild-type GSTP1 or CYP17 genes when combined with LOH/MSI in steroid metabolism genes may play a role in ER and/or PR negative breast cancers. These data support the hypothesis that genes related to steroid metabolism are important in the characterization of breast cancer and that the analysis of single polymorphisms may not be sufficient.

Comparative analysis of short tandem repeat data obtained by automated and gel electrophoresis techniques.

Short tandem repeats (STRs) are commonly used as genetic markers. The detection and analysis of STRs can be used to gather information on polymorphisms of interest to forensic geneticists. Denaturing polyacrylamide gel electrophoresis (PAGE) is an affordable method for the detection of minor sequence changes in DNA, while capillary electrophoresis (CE) is the gold standard for genotyping analysis. This appears to be the first study to directly compare data obtained using the two electrophoretic techniques. We analyzed genomic DNA from 209 individuals to compare genotyping results from seven Combined DNA Index System (CODIS) STR markers obtained by both techniques. The automated electrophoresis was carried out using a MegaBACETM 1000 DNA analysis system. Full concordance was found in 1297 of 1308 STR allele calls. Kappa and McNemar-Bowker tests indicated that there were no statistically significant differences between the results from the two methods. There was no statistically significant difference in precision between denaturing PAGE followed by silver nitrate staining, despite a longer protocol, compared with CE when applied to population studies. STR allele frequency data from non-automated genotyping techniques seem to be just as reliable as from automated genotyping methods.

Molecular epidemiology of HFE gene polymorphic variants (C282Y, H63D and S65C) in the population of Espírito Santo, Brazil.

Hereditary hemochromatosis (HH) is an autosomal recessive disorder that leads to progressive iron accumulation and may cause cirrhosis, hepatocellular carcinoma, diabetes, and heart failure. Most cases of HH have been linked to mutations in genes associated with iron homeostasis. There have been three major variants in the high Fe (HFE) gene associated with the disease: C282Y, H63D and S65C. In this context, we aimed to evaluate the prevalence of the polymorphic variants (C282Y, H63D and S65C) of the HFE gene in the population of the Espírito Santo State (ES), Brazil by analyzing three different groups: general population (N = 120), Pomeranian descendants (N = 59), and patients with HH (N = 20). Using genomic DNA extracted from peripheral blood, polymorphic variant identification was performed by polymerase chain reaction-restriction fragment length polymorphism. Statistically significant differences were observed for genotype distribution of C282Y (P < 0.001) and H63D (P = 0.013) between the general population and the patients diagnosed with HH. This is the first study to analyze HFE gene allele frequencies for the general population, Pomeranian subpopulation, and patients with HH of ES, Brazil.