There is almost complete linkage disequilibrium (Lewontin D' = 0.95) between the rs20417 polymorphism 5' of PTGS2 and rs5275 3' of PTGS2. Similarly, one PTGS2 haplotype carrying the variant allele of rs5275 was associated with a decrease in breast cancer risk. Here, PTGS2 is linked to breast carcinoma.