Preoperative CCL23 serum levels did not differ depending on tumor localization (iCCA, Klatskin tumor, distal CCA, gallbladder cancer), T-stage, M-stage (patients who were still eligible for tumor resection), and BTC tumor grading or resection status (Figures 2(a)–2(f)). The gene discussed is CCL23; the disease is Klatskin's tumor.