KL and neoplasm: To investigate the clinical significance of Klotho in hepatocarcinogenesis, we first evaluated immunohistochemical Klotho staining intensity in tumor specimens from 52 patients with HCC and classified these hepatoma samples into four categories: negative staining intensity (grade 0) for 1 case, weak staining intensity (grade I) for 10 cases, moderate staining intensity (grade II) for 18 cases, and strong staining intensity (grade III) for 23 cases (Figure 1A).