HLA-G expression in gastric cancer.
BACKGROUND
Ectopic HLA-G expression in tumor cells may indicate immune escape from the host immune defense via the inhibitory receptor on natural killer (NK) cells. However, there is little information on HLA-G expression in gastric cancer.


METHODS
HLA-G expression was immunohistochemically analyzed in 115 gastric cancer patients and the clinical implications of its expression in gastric cancer were assessed. Moreover, NK cell infiltration into the primary tumor was evaluated using anti-CD57 antibodies.


RESULTS
The HLA-G-positive group had a more differentiated histology, less nodal invasion and earlier clinical stage than the HLA-G-negative group and these differences were significant. The 5-year survival rate in the HLA-G-positive group was 78%, which was significantly higher than that in the HLA-G-negative group (51%). NK cell infiltration into the tumor tended to be negatively correlated with HLA-G expression.


CONCLUSIONS
Our results suggest a high frequency of HLA-G expression in early gastric cancer. However, this may not be directly related to aggressive tumor behavior via escape from the host antitumor immune defense. Further investigation is required.
Ishigami
Sumiya
S
Surgical Oncology, Kagoshima University School of Medicine, Kagoshima, Japan. Ishiga@m.kufm.kagoshima-u.ac.jp
Natsugoe
Shoji
S
Miyazono
Futoshi
F
Nakajo
Aikihiro
A
Tokuda
Koki
K
Matsumoto
Masataka
M
Okumura
Hiroshi
H
Douchi
Tsutomu
T
Hokita
Shuichi
S
Aikou
Takashi
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006680:HLA Antigens / Q000096:biosynthesis*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis*; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000276:immunology*; D014327:Trophoblasts / Q000276:immunology
D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I