This RCT showed that PFS was improved in patients with COX-2 overexpression.30 The potential mechanism was as follows: the EGFR signaling pathway is evidently correlated with COX-2 pathways, and PG produced by COX-2 may activate the EGFR signaling pathway and increase the levels of COX-2 and PGE2 in tumor cells. The gene discussed is PTGS2; the disease is neoplasm.