Among the genes displaying the most significant differences in methylation, SERPINB5 (serpin family B member 5) and S100A6 (S100 calcium binding protein A6) hypermethylation, and CAT (catalase) and BNC1 (basonuclin 1) hypomethylation were implicated in radioresistance of NSCLC. This evidence concerns the gene CAT and non-small cell lung carcinoma.