PGR and breast cancer: Our analysis of rs45446698 genotypes in 90,916 cases and 89,893 controls from BCAC, however, provides robust evidence of an association of the CYP3A7*1C allele with breast cancer risk overall (OR = 0.94, P = 0.002) and a more pronounced protective effect on ER + /PR + breast cancers (OR = 0.86, P = 6.9 × 10−8).