Laser capture microdissection in comparative proteomic analysis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most frequent visceral neoplasia worldwide and is a multifactorial and multistage pathogenesis that finally leads to the deregulation of cell homeostasis. A main problem with the analysis of HCC tissue samples, either at the level of proteins or genes, is the heterogeneous nature of the sample. Laser capture microdissection (LCM) may allow the more ready identification of differences in protein expression of selected cell types or areas of tissue and allows procuring a microscopic region as small as 3-5 microm in diameter. Here we applied the LCM to the isolation of hepatocyte for comparative proteomic analysis of hepatitis B-related HCC and surrounding nontumorous tissues. Proteome alterations were observed using two-dimensional polyacrylamide gel electrophoresis and electrospray ionization tandem mass spectrometry, and alterations in the proteome were examined. LCM was found to eliminate hemoglobin from homogenization of the HCC tissue, demonstrating its capacity of resolving the problem of heterogeneity and contamination in tissue samples. Twenty protein spots were selected and eleven proteins significantly altered in the surrounding nontumorous tissues and HCC tissues. Of the proteins that were selected, peroxiredoxin 2, apolipoprotein A-I precursor, 3-hydroxyacyl-CoA dehydrogenase type II, and 14.5-kDa translational inhibitor protein appear to be novel candidates for useful hepatitis B-related HCC markers. This study indicated LCM is a useful technological method in proteomic study of cancer tissue. The proteins revealed in this experiment can be used in the future for studies pertaining to hepatocarcinogenesis, or as diagnostic markers and therapeutic targets for HCC associated with Hepatitis B virus infection.