Plac1 is a tumor-specific antigen capable of eliciting spontaneous antibody responses in human cancer patients.
Immunoselection and tumor evasion constitutes one of the major obstacles in cancer immunotherapy. A potential solution to this problem is the development of polyvalent vaccines, and the identification of more tumor-specific antigens is a prerequisite for the development of cancer vaccines. To identify novel tumor-specific antigens, suppression subtractive hybridization (SSH) was performed to isolate genes differentially expressed in human hepatocellular cancer (HCC) tissues. PLAC1 (PLACenta-specific 1) was one of the genes identified highly expressed in HCC tissues but not in paired noncancerous tissues. Further analyses revealed its expression in several other types of cancer tissues as well as tumor cell lines, but not in normal tissues except for placenta. Among HCC samples tested, 32% (22/69) showed PLAC1 mRNA expression while the protein was detected in 23.3% (7/30). A serological survey revealed that 3.8% (4/101) of HCC patients had anti-PLAC1 antibody response, suggesting the immunogenicity of PLAC1 in HCC patients. PLAC1 represents a new class of tumor associated antigen with restricted expression in placenta and cancer tissues, that may serve as a target for cancer vaccination.
Dong
Xue-Yuan
XY
Department of Immunology, Peking University Health Science Center, Beijing, China.
Peng
Ji-Run
JR
Ye
Ying-Jiang
YJ
Chen
Hong-Song
HS
Zhang
Li-Jie
LJ
Pang
Xue-Wen
XW
Li
Yan
Y
Zhang
Yu
Y
Wang
Shan
S
Fant
Michael E
ME
Yin
Yan-Hui
YH
Chen
Wei-Feng
WF
D000912:Antibodies, Neoplasm / Q000097:blood*; D000917:Antibody Formation; D015152:Blotting, Northern; D015153:Blotting, Western; D019496:Cancer Vaccines / Q000276:immunology; D006528:Carcinoma, Hepatocellular / Q000276:immunology*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000276:immunology*; D009693:Nucleic Acid Hybridization / Q000379:methods; D011257:Pregnancy Proteins / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013382:Subtraction Technique
D000912:Antibodies, Neoplasm; D019496:Cancer Vaccines; C415583:PLAC1 protein, human; D011257:Pregnancy Proteins; D011994:Recombinant Proteins