Clinical implications of human leukocyte antigen class I expression in endometrial cancer.

Decreased expression of human leukocyte antigen (HLA) class I molecules, which is found in several types of cancer, is associated with worse clinical prognosis in cancer patients. The present study was undertaken to investigate the association of immunohistochemical HLA class I expression patterns with clinicopathological factors and prognosis in 96 endometrial cancer patients. HLA class I is composed of a heavy chain (HC-10) and a β2-microglobulin (β2-m) light chain. The HLA class I expression patterns were classified as positive when both HC-10 and β2-m were strongly stained and negative in all other cases. The negative staining pattern was associated with advanced International Federation of Gynecology and Obstetrics stage (P<0.001), lymphovascular space involvement (LVSI) (P=0.003) and lymph node metastasis (P=0.005). Moreover, these cases exhibited worse progression-free survival (PFS) and overall survival (OS) rates compared with positive cases (P=0.005 and P=0.014, respectively). However, the multivariate analysis did not identify HLA class I expression as an independent predictive factor for PFS and OS. In conclusion, HLA class I expression may be useful for predicting postoperative outcome in endometrial cancer, as well as well-known predictive prognostic factors, such as lymph node metastasis and LVSI.