MKI67 and hepatocellular carcinoma: Staining for Ki-67 was used to identify hepatocyte nuclei in the S-phase of the cell cycle (for details, see Materials and methods); five HCC were studied: 77.3±9.2% of 343 Ki-67-positive hepatocyte nuclei evaluated displayed proTGFα. A high co-incidence of DNA synthesis and proTGFα was recently shown also for hepatocyte nuclei in cirrhotic liver (Grasl-Kraupp et al, 2002).