In FAP patients treated with low-dose EC-Aspirin (100 mg daily for 3 months), 24 h after the last administration, the acetylation of platelet COX-1 at Serine529 was significantly higher than in colorectal adenomas and normal tissue collected on the left and right colon and rectum (Figure 3A). Here, PTGS1 is linked to Familial adenomatous polyposis.