Fig. 1

Putative mechanisms of action of low-dose aspirin in platelets and tumor cells in suppressing tumor growth. Low-dose aspirin exerts an inhibitory effect on platelet aggregation by suppressing production of TXA2 through inhibition of COX-1 in platelets. Thus, low-dose aspirin prevents platelets from binding to tumor cells, resulting in suppression of distant metastasis. On the other hand, PGE2, which is upregulated in colon cancer cells, is suppressed by low-dose aspirin, leading to inhibition of tumor growth and angiogenesis. COX-1 cyclooxygenase-1, COX-2 cyclooxygenase-2, PGE2 prostaglandin E2, TXA2 thromboxane A2