HLA-F expression is a prognostic factor in patients with non-small-cell lung cancer

Human leukocyte antigens (HLA)-E, -F and -G are referred to as non-classical HLA class I antigens. Among them, the clinical relevance of HLA-E and HLA-G has been intensively investigated, but that of HLA-F remains unknown. In this study, HLA-F expression in 83 primary non-small-cell lung cancer (NSCLC) lesions and corresponding adjacent normal tissues were analyzed with immunohistochemistry. Relevance of HLA-F expression with clinical parameters and patient survival was evaluated. Data revealed that HLA-F expression was observed in 24.1% (20/83) of the NSCLC primary lesions but not in adjacent normal lung tissues. HLA-F expression was not significantly relative to clinicoparameters including patient age, gender, tumor histological type, grade of tumor differentiation and TNM stage. Unexpectedly, patients with HLA-F positive expression had a significantly worse prognosis (p = 0.017). The median overall survival for the patients with HLA-F positive was 10.0 months (range: 4.4-18.3 months) and with HLA-F negative was 17.0 months (range: 10.4-23.6 months), respectively. Multivariate analysis revealed that HLA-F could be an independent prognostic factor with the hazard ratio of 5.12 [95% confidential Intervals (CI): 1.8-14.3]. Summary, this study was for the first time to provide the evidence that HLA-F expression was of clinical significance in tumor patients and that its expression was associated with a poor survival and could be a prognostic indicator in patients with NSCLC.