BRCA1 and BRCA2 genes are responsible for 5-10% of breast and ovarian cancer 
cases. However, the vast majority of ovarian and breast cancer cases do not 
display the hereditary form of the disease. Estrogen-metabolizing genes may also 
contribute to the predisposition of breast or ovarian cancer. Polymorphic 
variants of the estrogen-metabolizing gene, CYP17, have been associated with the 
risk of hormone-related cancers. In this study we investigated the CYP17 
polymorphisms in ovarian cancer patients harboring mutations in the BRCA1 and 
BRCA2 genes, patients displaying familial characteristics but not carrying 
mutations and patients with sporadic ovarian cancer. Association between the 
allele frequencies, the CYP17 genotype and tumor characteristics or clinical 
parameters was evaluated. Our data suggest evidence for an association between 
ovarian cancer risk and the CYP17 genotype in the subgroup of patients with 
familial disease in whom no mutations in the BRCA genes are found. Although 
there were no statistically significant differences in the genotype distribution 
between the control group and the subgroup of patients with BRCA mutations, the 
frequency of the CYP17 A2 allele was significantly higher in the subgroup of 
patients without BRCA mutations. We found a four- to eightfold higher risk in 
ovarian cancer patients with family history but without BRCA mutations. Our data 
indicate that the CYP17 A2 allele polymorphism may confer an increased risk and 
can provide a biomarker for ovarian cancer patients in whom no mutations in the 
BRCA genes are observed.