The total protein expression of RRM2 was strongly elevated in BRCA, KIRC, COAD, HNSC, LIHC, LUAD, OV, pancreatic adenocarcinoma (PAAD), and UCEC patients (Fig. 2A, P < 0.05, P < 0.001). The gene discussed is RRM2; the disease is pancreatic adenocarcinoma.