PTGS2 and neoplasm: We found that only 33, 36% and 45% of patients had acetylated COX-2 (% AceCOX-2 >10) in their tumor tissues when taking aspirin at 100 mg/d, 100 mg/BID, and 300 mg/d doses, respectively (i.e., 4 out of 12, 4 out of 11, and 5 out of 11 CRC patients, respectively) (Figure 7B).