PTGS2 and breast carcinoma: When we evaluated the associations between ever use of aspirin and breast cancer risk stratified by COX-2 genotype, the decreased OR observed among ever users of aspirin who carried at least one variant C allele of COX-2 .8473 (OR = 0.7, 95% CI = 0.5 to 0.9) compared with nonusers carrying the wild-type TT genotype (Table 3) was similar to the overall OR obtained from ever users of aspirin.