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. This evidence concerns the gene PTGS2 and colorectal carcinoma.