Aspirin dosing in our CD1 Nude mouse model [36, 37], which mimicked low-dose aspirin use in humans, based on profound platelet COX-1 inhibition but an absence of systemic COX-2 inhibition, did not increase the sensitivity of MC38 mouse CRC cell tumours to EPA in vivo, in direct contrast to the corresponding in vitro data. The gene discussed is PTGS1; the disease is colorectal carcinoma.