EVALUATION OF PROLIFERATIVE ACTIVITY IN HEPATOCELLULAR-CARCINOMA BY KI-67 IMMUNOSTAINING OF PARAFFIN-EMBEDDED TISSUES AFTER ANTIGEN RETRIEVAL

Ki-67 is considered to be a marker of cell proliferation. Immunohistochemically, Ki-67 has been demonstrated on human fresh or frozen tissues but not on paraffin-embedded tissues in which antigenicity of Ki-67 is masked. In this study, we examined the antigenicity of Ki-67 on formalin-fixed and paraffin-embedded sections after autoclave heating. Using this method, we evaluated the proliferative activity in hepatocellular carcinomas (HCCs) with various histological grades of malignancy. The number of Ki-67-positive cells significantly increased in parallel with the histological grade of HCCs, indicating that the assessment of proliferative activity by Ki-67 immunostaining may be useful to evaluate the malignant potential in HCCs.