Aim: To discuss the expression of human leukocyte antigen (HLA) class I antigens in gastric cancer and correlate these with pathologic type and TNM stage.
Methods: The expression of HLA class I antigen was detected by immunohistochemistry in 185 specimens of gastric cancer, 20 gastric cancer specimens with lymphatic metastasis and 22 controls of normal gastric mucosa using four monoclonal antibodies.
Results: The expression of HLA class I antigen (B/C locus) was significantly downregulated in gastric cancer and in lymphatic metastasis than that in normal gastric mucosa (chi2=7.712, P<0.05). The expression of other HLA class I antigens was also downregulated, but the change was slight. There was no relationship between the downregulation of HLA class I antigen and that of beta2m and LMP2. The expression of HLA class I (B/C locus) was statistically correlated with pathologic stage in gastric adenocarcinoma (chi2=4.164, P<0.05).
Conclusion: The expression of HLA class I antigen (B/C locus) was obviously downregulated in gastric cancer and in lymphatic metastasis. This abnormal expression would provide the tumor cells with a way to avoid immunological recognition.