Ki-67 is a well-known proliferation marker for the evaluation of cell proliferation, many previous studies had suggested that Ki-67 independently predicts cancer progression [10], and a study by Kitamura et al. mentioned that FDG uptake was also higher in Ki-67-positive lesions [11], but it is unclear whether the Ki-67 index (the percent positive frequency of Ki-67 protein labeling in HCC tumors) in HCC is useful in the interpretation of 18F-FDG PET/CT. The gene discussed is MKI67; the disease is hepatocellular carcinoma.