Regarding the tumor stage, RRM2 expression was significantly associated with Skin Cutaneous Melanoma (SKCM) in stage I group, BRCA, COAD, LUAD, LUSC and PAAD in stage II group, KIRP, LIHC and THCA in stage III group, adrenocortical carcinoma (ACC), KICH, KIRC and TGCT in stage IV group (Fig 2I–2L and S1P-S1X Fig in S1 File). This evidence concerns the gene RRM2 and pancreatic adenocarcinoma.