PTGS1 and polyp of large intestine: Investigation of SNPs in genes believed to be relevant to the mechanism of action of aspirin [Prostaglandin G/H Synthase (PTGS); also known as Cyclooxygenase (COX)-1 and -2] in post hoc analyses of randomized colorectal polyp prevention trials of aspirin has demonstrated a possible interaction between aspirin and PTGS2 SNP rs4648310 (6).