Prognostic implications of human leukocyte antigen class I expression in patients who underwent surgical resection for non-small-cell lung cancer

Background: The purpose of the present study was to clarify the prognostic significance of human leukocyte antigen (HLA) class I expression in patients with non-small-cell lung cancer who underwent complete surgical resection. Patients and methods: The expression of HLA class I molecules was evaluated in 403 resected NSCLC specimens using immunohistochemistry. The results were scored as the percentage of stained tumor cells and were categorized into three groups: 0%-24% (decreased), 25%-79% (heterogeneous), and 80% or more (normal). Results: The expression of HLA class I was evaluated in 124 tumors in the normal expression group, 181 tumors in the heterogeneous expression group, and 98 tumors in the decreased expression group. The 5-year survival rate of all patients after surgery according to the HLA class I expression in the normal, heterogeneous, and decreased groups was 76.6%, 65.9%, and 76.1%, respectively. The prognosis was significantly better in the normal expression group than in the heterogeneous group. Normal HLA class I expression also correlated with favorable survival in patients with stage I disease. Conclusions: The normal expression of HLA class I was associated with a favorable prognosis compared with the heterogeneous expression group, but no significant difference was observed between the normal expression and decreased expression groups. (C) 2013 Elsevier Inc. All rights reserved.