Objective      To detect and validate the new specific antigens associated with hepatocelluar carcinoma (HCC). Methods     Total proteins from 15 HCC tissues and their adjacent tissues were extracted respectively. Western blotting was used to detect the interactions between the total proteins and autologous serums of the 15 HCC patients. Various proteins of the 15 mixed total proteins were separated and dyed by two-dimensional electrophoresis (2-DE). Image analysis was employed to compare the expression differences of proteins extracted from HCC tissues and those from their adjacent tissues. The obtained proteins with different expression levels were analyzed and identified with matrix-assisted laser desorption/ionization-time-of-flight with two mass analyzers for tandem mass spectrometry (MALDI-TOF MS/MS)

and searched for their sequences in bioinformatics network database

and then confirmed by immunohistochemical assay and Western blotting respectively. Results       The results of image comparison from 2-DE dyeing proteins revealed that a total of 90 protein spots with different expression levels were found. And among the 19 protein spots eventually identified by MALDITOF MS/MS

15 proteins were up-regulated

and 4 down-regulated. Immunohistochemical assay and Western blotting confirmed that compared with the proteins from the adjacent tissues

DnaJ homolog subfamily B member 11 (DNAJB11) was significantly enhanced in these up-regulated proteins

and proteasome subunit alpha type 3 (PSMA3) was the most obviously down-regulated protein from HCC tissues. Conclusion     Hepatocelluar carcinoma associated antigen

DNAJB11 is up-regulated

while PSMA3 is down-regulated in the HCC tissue.