CABYR is a novel cancer-testis antigen in lung cancer.
OBJECTIVE
Cancer-testis (CT) antigens are often expressed in a proportion of tumors of various types. Their restricted normal tissue expression and immunogenicity make them potential targets for immunotherapy. CABYR is a calcium-binding tyrosine phosphorylation-regulated fibrous sheath protein initially reported to be testis specific and subsequently shown to be present in brain tumors. This study was to determine whether CABYR is a novel CT antigen in lung cancer.


METHODS
mRNA expression of CABYR-a/b (combination of CABYR-a and CABYR-b) and CABYR-c was examined in 36 lung cancer specimens, 14 cancer cell lines, and 1 normal cell line by conventional and real-time reverse transcription-PCR. Protein expression of CABYR was analyzed in 50 lung cancer tissues by immunohistochemistry. Antibodies specific to CABYR were analyzed in sera from 174 lung cancer patients and 60 healthy donors by ELISA and Western blot.


RESULTS
mRNA expression of CABYR-a/b and CABYR-c was observed, respectively, in 13 and 15 of 36 lung cancer tissues as well as in 3 and 5 of 14 cancer cell lines, whereas neither of them was observed in adjacent noncancerous tissues or the normal cell line. Protein expression of CABYR-a/b and CABYR-c was observed, respectively, in 20 and 19 of 50 lung cancer tissues. IgG antibodies specific to CABYR-a/b and CABYR-c were detected, respectively, in 11% and 9% of sera from lung cancer patients but not from the 60 healthy donors.


CONCLUSIONS
CABYR is a novel CT antigen in lung cancer and may be a promising target for immunotherapy for lung cancer patients.
Luo
Chonglin
C
Key laboratory of Cell Proliferation and Regulation of Ministry of Education, Beijing Normal University, China.
Xiao
Xueyuan
X
Liu
Danhui
D
Chen
Shaosong
S
Li
Mingying
M
Xu
Anjian
A
Liu
Jifu
J
Gao
Shugeng
S
Wu
Shanshan
S
He
Dacheng
D
D000912:Antibodies, Neoplasm / Q000097:blood / Q000276:immunology; D000918:Antibody Specificity; D000951:Antigens, Neoplasm / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics / Q000276:immunology; D002135:Calcium-Binding Proteins / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics / Q000276:immunology; D045744:Cell Line, Tumor; D006367:HeLa Cells; D006801:Humans; D007150:Immunohistochemistry; D020014:K562 Cells; D008175:Lung Neoplasms / Q000097:blood / Q000235:genetics / Q000276:immunology*; D008297:Male; D010750:Phosphoproteins / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics / Q000276:immunology; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D013737:Testis / Q000276:immunology
D000912:Antibodies, Neoplasm; D000951:Antigens, Neoplasm; C448922:CABYR protein, human; D002135:Calcium-Binding Proteins; D010750:Phosphoproteins; D020033:Protein Isoforms; D012333:RNA, Messenger