CYP2A7 and ovarian cancer: The strongest association with a validated deletion was observed for ovarian cancer, detected in 75/1962 (3.8%) unaffected carriers and 4/357 (1.1%) affected carriers (RR=0.50, P=7 × 10−3) overlapping the CYP2A7 locus (19q13.2; Supplementary Figure S2).