Proteomic alterations of the variants of human aldehyde dehydrogenase isozymes correlate with hepatocellular carcinoma.

To develop novel markers for hepatocellular carcinomas (HCC), 10 cases were analyzed by 2-dimensional electrophoresis (2DE) and matrix-assisted laser desorption ionization mass spectrometry. Results were compared to those of paired adjacent nontumorous liver tissues. Comparative analysis of the respective spot patterns in 2DE revealed that 3 variants of class 3 aldehyde dehydrogenase (ALDH-3) newly appeared while 2 variants of ALDH-2 diminished to undetectable levels in HCC. However, 4 ALDH-1 variants with different pIs remained unaffected. This pattern of concomitant appearance and disappearance of ALDH-3 and ALDH-2 variants was consistently observed in all HCC tissues. Our results suggest that alterations of ALDH isozyme variants may be closely correlated to HCC and that proteomic analysis of these proteins might be a novel approach to identify the molecular events in detail during hepatocarcinogenesis.