Evaluation of HLA-DR and HLA-DQ expression in gastric cancer tissues.

Background And Objectives: Despite recent advances in understanding the gastric cancer (GC) biology, the precise molecular mechanism of gastric carcinogenesis and role of deregulated immune responses in GC progression are still not well understood. In this study, mRNA levels of human leukocyte antigen (HLA)-DRA and -DQA1 were assessed in GC patients to find a potential association between expression of these HLA-II molecules and gastric carcinogenesis.

Methods: Using quantitative real-time (qRT)-PCR, mRNA levels of HLA-DRA and -DQA1 were assessed in 20 pairs of matched GC and normal tissues.

Results: Our results showed that overall mRNA level of HLA-DRA was decreased in the tumor samples relative to control tissues (median fold change [FC] = 0.693; P = 0.445). Overall HLA-DQA1 level was increased in the tumor samples relative to control tissues (median FC = 1.659; P = 0.5117). However, the mentioned data were not statistically significant. Meanwhile, using a ≥ 2.5 FC as the cutoff to determine upregulation or downregulation, 35% of patients showed a downregulated expression of HLA-DRA, while 10% of those showed upregulation in HLA-DRA expression. Upregulation and downregulation of HLA-DQA1 expression were detected, respectively, in 35% and 25% of samples. A strong positive correlation was determined between HLA-DRA and HLA-DQA1 levels in tumor tissues (r = 0.7298; P = 0.0003).

Conclusion: The results reported here along with future studies can be useful to understand the interplay between immune system and GC, therefore, may be helpful to design an effective immune-based therapy.