As COX-2 overexpression is an important step in colon tumorigenesis [30,31] and as aspirin is more specific to COX-1 (IC50 1.67 μM) than to COX-2 (IC50 278 μM), the direct inhibition of COX-1 by low-dose aspirin is insufficient to explain its observed anti-cancer effects [18,32]. The gene discussed is PTGS1; the disease is cancer.