To explore whether loss-function of p53 affects RNR in cancer cells, we compared the RRM1 and RRM2 levels of TP53 wild type with that of TP53 mutant cancer cell lines, including lung carcinoma A549 (TP53 wild type) and H1299 (TP53 mutant), pancreatic cancer LNCAP (TP53 wild type) and PC3 (TP53 mutant), neuroblastoma SKN-SH (TP53 wild type) and SKN-BE (TP53 mutant), rhabdomyosarcoma Rh18 (TP53 wild type) and Rh30 (TP53 mutant) cells. Here, RRM2 is linked to cancer.