CYP17A1 and breast cancer: Consistent with most previous studies and a recent meta-analysis was our failure to find any evidence for an association between the CYP17 genotype defined by the – 34 promoter region T→C nucleotide-substitution polymorphism and risk of breast cancer overall, or within premenopausal or postmenopausal women, whether the genotype be defined under a codominant or a recessive mode of inheritance.