Clinical implication of human leukocyte antigen ( HLA )‐ F expression in breast cancer

Human leukocyte antigen ( HLA )‐ F is one of the non‐classical HLA class I molecules that protects the fetus in pregnancy. HLA ‐ F expression was immunohistochemically examined and the association between clinical parameters and HLA ‐ F expression was analyzed. Cancerous HLA ‐ F and stromal HLA ‐ F ‐positive infiltrating cells were detected in 91 (40.0%) and 186 (81.6%) cases, respectively. HLA ‐ F positivity in cancer cells was significantly associated with tumor size ( P  < 0.05). There was a weak correlation between HLA ‐ F positivity of cancer cells and HLA ‐ F positive infiltrative cells ( P  < 0.01, r = 0.11). HLA ‐ F positivity did not affect patients' survival in 209 breast cancer. However, confined to stage II breast cancer, the HLA ‐ F positive group showed significantly poorer outcomes than the HLA ‐ F negative group ( P  < 0.05). The present study provides the first evidence that HLA ‐ F positivity in breast carcinoma affects clinicopathological factors and could be selected as a prognostic marker for limited clinical stage.