"The purpose of this study was to elucidate the function of protein kinase C (PKC) α in human
hepatocellular carcinoma (HCC). Histoimmunopathologic techniques were used to determine the
localization and/or expression of PKCα, phospho-mitogen-acrivated protein kinase (MEK) and multidrug
resistance 1 (MDR1) in HCC biopsies. Expression of PKCα, phospho-MEK and MDR1 was significantly
increased in the region of HCC location compared with the non-tumor location. The HCC tissues were
classified as cytosolic type, where PKCα was deposited in the cytoplasm in > 50% of cells, or membranous
type for others. The results showed that the higher expression levels of phospho-MEK and MDR1 in
HCC location were significantly associated with those patients whose cells were of the membranous type.
Moreover, the expression of MDR1 in HCC location was also significantly associated with the phosphoMEK, and was significantly higher in the patients with anti-HCV negative readings. The results indicate
that elevated expression of MDR1 in HCC patients with non-HCV infection may be mediated through
PKC signaling pathway."