PTGS2 and neoplasm: Recent studies have shown PTGS2 expression to be upregulated in a number of human tumor types.16, 17 Inhibitors of PTGS2 have been reported to reduce the proliferation rate of tumor cell lines grown and acted as radiosensitizing agents.18 NF‐κB initiates the inflammatory response by regulating the expression of PGS2 and other cytokines.19 As a result, we suppose that NF‐κB affecting radiation resistance in tumor is via regulation of PTGS2.