Clinical-pathological implication of human leukocyte antigen-F-positive gastric adenocarcinoma

Background: Human leukocyte antigen (HLA)-F is a nonclassical HLA class I molecule that shows aberrant expression in cancer cells. Although the clinical implications of HLA-F expression in cancer patients have been described, the specific significance of this antigen in gastrointestinal cancer remains unclear. The present study examined the expression pattern and clinical implications of HLA-F in gastric adenocarcinoma. Patients and methods: HLA-F expression was assessed in 179 patients by immunohistochemistry, and its association with clinical parameters including patient survival was analyzed. Results: HLA-F expression was positive in 30.7% (55/179) of patients and in 50.0% (90/179) of peritumoral infiltrating lymphocytes. HLA-F expression in gastric adenocarcinoma was significantly correlated with the depth of invasion, nodal involvement, and lymphatic and venous invasions (P < 0.01, all). HLA-F positivity of infiltrating cells near the tumor showed no correlation with clinicopathological features. HLA-F-positive patients had a significantly worse prognosis than HLA-F-negative patients (P = 0.012). However, HLA-F expression was not an independent prognostic factor in multivariate analysis. Conclusions: The present study provides the first evidence that neo-HLA-F expression is of clinical significance in gastric adenocarcinoma. HLA-F expression in gastric adenocarcinoma may promote the aggressive behavior of tumors by suppressing the activity of antitumor immune effector cells.