PTGS2 and Familial adenomatous polyposis: Since in vitro and in vivo studies showed that the EGFR signaling pathway is involved in COX-2 expression [276], a trial evaluating combined treatment with the non-specific COX-2 inhibitor sulindac 150 mg twice daily and the EGFR tyrosine kinase inhibitor erlotinib 75 mg daily vs. placebo was performed in FAP patients.