Epithelial ovarian cancer (EOC) is one of the most mortal carcinomas in females. Immune systems can recognize EOCs; however, a defect of HLA class I ex-pression is known to be a major mechanism for escape from immune systems, resulting in poor prognosis. The purpose of this study is to find novel relations between immunological response and other clinical factors. We investigated expression of immunological components in 122 cases of EOC for which opera-tions were performed in the period from 2001 to 2011. We stained EOC specimens immunohistochemically using an anti-pan HLA class I monoclonal antibody (EMR 8-5) and CD3, CD4, CD8 antibodies, and we analyzed correla-tions with immunological parameters and clinical factors. In multivariate analy-sis used the Cox proportional hazards model, independent prognostic factors for overall survival in advanced EOC were low expression level of HLA class I (RR= 1.97, 95%CI=1.01-3.83; p=0.046) and loss of intraepithelial cytotoxic T lympho-cyte (CTL) infiltration (RR=2.11, 95%CI=1.06-4.20; p=0.033). Interestingly, almost all platinum-resistant cases showed a significantly low rate of intraepi-thelial CTL infiltration in the χ square test (positive vs negative: 9.0% vs 97.7%, p<0.001). A logistic regression model revealed that low CTL infiltration rate was an independent factor of platinum resistance in multivariate analysis (OR=3.77, 95%CI=1.08-13.12; p=0.037). Platinum-resistant EOC shows poor immunological responses. The immune escape system of EOC may be one of the mechanisms of platinum resistance
- Received May 22, 2014.
- Revision received September 1, 2014.
- Accepted September 23, 2014.
- Copyright © 2014, American Association for Cancer Research.