CYP17 promoter polymorphism and breast cancer in Australian women under age forty years

Abstract

Background: The cytochrome P450c17α enzyme functions in the steroid biosynthesis pathway, and altered endogenous steroid hormone levels have been reported to be associated with a T to C polymorphism in the 5' promoter region of the CYP17 gene. Because steroid hormone exposure is known to influence breast cancer risk, we conducted a population-based, case-control-family study to assess the relationship between the CYP17 promoter polymorphism and early-onset breast cancer. Methods: Case subjects under 40 years of age at diagnosis of a first primary breast cancer, population-sampled control subjects, and the relatives of both case and control subjects were interviewed to record family history o..