To verify whether or not SESN2, FN1, TRAF4, CDKN1A, COX-2, DDB2 and FDXR could be related to cellular radioresistance in NSCLC cells, the mRNA expression of these genes was compared between radioresistant A549 and radiosensitive NCI-H460 cells through real-time RT-PCR (Fig. 5B). Here, DDB2 is linked to non-small cell lung carcinoma.