Since PTGER4 was shown to be the main PGE2 receptor expressed on CRC cells (Supplementary Fig. 11j), we treated cells with the PTGER4 antagonist ONO-AE3, which significantly impaired TFF3-induced PTGS2 expression (Supplementary Fig. 11k) and PGE2-induced cAMP generation (Supplementary Fig. 11l), STAT3 phosphorylation and PTGS2 expression (Supplementary Fig. 11m). This evidence concerns the gene PTGS2 and colorectal carcinoma.