AIM:To gain tumor endothelium associated antigen genesfrom human liver cancer vascular endothelial cells (HLCVECs)cDNA expression library,so as to find some new possibletargets for the diagnosis and therapy of liver tumor.METHODS:HLCVECs were isolated and purified from afresh hepatocellular carcinoma tissue sample,and werecultured and proliferated in vitro.A cDNA expression librarywas constructed with the mRNA extracted from HLCVECs.Anti-sera were prepared from immunized BALB/c micethrough subcutaneous injection with high dose of fixedHLCVECs,and were then tested for their specificity againstHLCVECs and angiogenic effects in vitro,such as inhibitingproliferation and inducing apoptosis of tumor endothelialcells,using immunocytochemistry,immunofluorescence,cell cycle analysis and MTT assays,etc.The identifiedxenogeneic sera from immunized mice were employed toscreen the library of HLCVECs by modified serologicalanalyses of recombinant cDNA expression libraries (SEREX).The positive clones were sequenced and analyzed by bio-informatics.RESULTS:The primary cDNA library consisted of 2×10~6recombinants.Thirty-six positive clones were obtained from6×10~5 independent dones by immunoscreening.Bio-informaticsanalysis of cDNA sequences indicated that 36 positive clonesrepresented 18 different genes.Among them,3 were newgenes previously unreported,2 of which were hypotheticalgenes.The other 15 were already known ones.Series analysisof gene expression (SAGE) database showed that ERP70,GRP58,GAPDH,SSB,S100A6,BMP-6,DVS27,HSP70 andNACalpha in these genes were associated with endotheliumand angiogenesis,but their effects on HLCVECs were stillunclear.GAPDH,S100A6,BMP-6 and hsp70 were identifiedby SEREX in other tumor cDNA expression libraries.CONCLUSION:By screening of HLCVECs cDNA expressionlibrary using sera from immunized mice with HLCVECs, the functional genes associated with tumor endotheliumor angiogenesis were identified.The modified SEREX,xenogeneic functional serum screening,was demonstratedto be effective for isolation and identification of antigengenes of tumor endothelium,and also for other tumor cellantigen genes.These antigen genes obtained in this studycould be a valuable resource for basic and clinical studiesof tumor angiogenesis,thus facilitating the developmentof anti-angiogenesis targeting therapy of tumors. AIM: To gain tumor endothelium associated antigen genes from human liver cancer vascular endothelial cells (HLCVECs) cDNA expression library, so as to find some new possibletargets for the diagnosis and therapy of liver tumor. METHODS: HLCVECs were isolated and purified from afresh hepatocellular carcinoma tissue sample, and were cultured and proliferated in vitro. A cDNA expression library was constructed with the mRNA extracted from HLCVECs. Anti-sera were prepared from immunized BALB / c microwrough subcutaneous injection with high dose of fixed HLCVECs, and were then tested for their specificity against HLCVECs and angiogenic effects in vitro, such as inhibitingproliferation and inducing apoptosis of tumor endothelial cells, using immunocytochemistry, immunofluorescence, cell cycle analysis and MTT assays, etc. The identified xenogeneic sera from immunized mice were employed toscreen the library of HLCVECs by modified serologicalanalyses of recombinant cDNA expression libraries ( SEREX). The positive clones were sequenced and analyzed by bio-informatics .RESULTS: The primary cDNA library consisted of 2 × 10 ~ 6 recombinants.Thirty-six positive clones were obtained from 6 × 10 ~ 5 independent dones by immunoscreening. Bio-informatics analysis of cDNA sequences that that 36 positive clonesrepresented 18 different genes. Among them, 3 were new genes previously unreported, 2 of which were hypothetical genes. The other 15 were already known ones. Series analysis of gene expression (SAGE) database showed that ERP70, GRP58, GAPDH, SSB, S100A6, BMP- 6, DVS27, HSP70 andNACalpha in these genes were associated with endotheliumand angiogenesis, but their effects on HLCVECs were stillunclear. GAPDH, S100A6, BMP-6 and hsp70 were identified by SEREX in other tumor cDNA expression libraries.CONCLUSION: By screening of HLCVECs cDNA expressionlibrary using sera from immunized mice with HLCVECs, the functional genes associated with tumor endothelium angiogenesis were identified. modified SEREX, xenogeneic functional serum screenin g, was demonstrated to be effective for isolation and identification of antigengenes of tumor endothelium, and also for other tumor cellantigen genes. These antigen genes obtained in this study can be a valuable resource for basic and clinical studies of tumor angiogenesis, thus facilitating the development of anti-angiogenesis targeting therapy of tumors.