CD8+ lymphocyte infiltration and apoptosis in hepatocellular carcinoma.
OBJECTIVE
Tumour-infiltrating lymphocytes (TILs) play a role in local anti-tumour immunity. Tumour cells may escape from immune surveillance by expressing RCAS1, a receptor-binding cancer antigen expressed on SiSo cells, which inhibits T cell growth. In this study, the correlation between the density of CD8+ TILs, tumour cell apoptosis, and tumour RCAS1 expression was investigated in hepatocellular carcinoma (HCC).


METHODS
We obtained tissues from 60 patients with surgically resected HCCs. CD8+ TILS, apoptotic cancer cells, and RCAS1 expressing cancer cells were identified by immunohistochemistry.


RESULTS
The density of CD8+ T cells in tumours (mean: 9.5/HPF, HPF: high power field) was significantly less than in non-cancerous hepatic lobules (17.8/HPF, p<0.001) and in relation to the progression of tumour stage. The density of CD8+ T cells in tumours positively correlated with the occurrence of tumour cell apoptosis, but did not correlate with RCAS1 protein expression.


CONCLUSIONS
CD8+ TILs may play a role in the occurrence of tumour cell apoptosis in HCC, but CD8+ TILs may not be controlled by RCAS1 in HCC.
Ikeguchi
M
M
Division of Operating Room, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, 683-8504 Yonago, Japan. masaike@grape.med.tottori-u.ac.jp
Oi
K
K
Hirooka
Y
Y
Kaibara
N
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000378:metabolism; D017209:Apoptosis; D018414:CD8-Positive T-Lymphocytes / Q000473:pathology*; D006528:Carcinoma, Hepatocellular / Q000276:immunology / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000276:immunology / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D016246:Lymphocytes, Tumor-Infiltrating / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D015996:Survival Rate
D000951:Antigens, Neoplasm; C120762:EBAG9 protein, human