Most human colorectal cancers exhibit marked elevation of cyclooxygenase-2 (COX-2) expression.4,5 Moreover, the COX-2 and prostaglandin E2 (PGE2) receptor subtypes are reportedly involved in intestinal carcinogenesis and activation of multiple signalling pathways.6–8 PGE2 receptor 2 (PTGER2) and PGE2 receptor 4 (PTGER4) receptors activate PGE2, triggering a series of events,9 with several studies indicating that PGE2 mediates the effects of chronic inflammation on colorectal cancer stem cell (CSC) expansion and chemoresistance.10,11. This evidence concerns the gene PTGER2 and colorectal cancer.