PTGS2 and polyp of large intestine: Comparison of total colorectal polyp number per participant between those allocated aspirin versus placebo according to genotype for each PTGS1, PTGS2, and HPGD SNP revealed that PTGS1 rs4837960 common homozygotes (G:G) and PTGS2 rs2745557 compound heterozygotes (G:A)-rare homozygotes (A:A) were associated with a statistically significant reduction in total colorectal polyp number in aspirin users versus nonaspirin users in contrast to the other genotype (Supplementary Fig. S1; Supplementary Table S2).