Clinical factors and biomarker profiles associated with patient outcome in endometrioid ovarian carcinoma - Emphasis on tumor grade

Objective: The role of clinicopathological factors and molecular markers in prognostic classification of endometrioid ovarian carcinoma (EnOC) is not established. Tumor grade is used in risk assessment, but the role of current 3-tier grading system has been challenged.

Methods: Clinicopathological factors and 12 immunohistochemical biomarkers (PR, ER, β-catenin, vimentin, ARID1A, HNF1-β, p53, p16, MIB-1, E-cadherin, c-erb-B2 and L1CAM) were analyzed as regards patient outcome in 215 contemporarily classified EnOCs.

Results: Of clinical parameters, grade and stage appeared as strong independent prognostic factors both for disease-free and disease-specific overall survival. Grades 1-3 distinguished clearly from each other in the survival analysis, whereas stages I-II and stages III-IV clustered with each other. PR, ER, nuclear β-catenin and vimentin positivity were associated with favorable overall outcome and clinical parameters, whereas abnormal expression of p53, overexpression of p16 and L1CAM positivity were associated with aggressive disease characteristics and poor survival. The frequency of good-prognosis markers PR and β-catenin gradually decreased and poor-prognosis markers p53, p16 and L1CAM gradually increased from grade 1-3. However, vimentin and ER were expressed at similar frequencies across different grades and presented with independent prognostic significance.

Conclusions: We found histological grade and disease stage, but not residual tumor, to be independent clinical prognostic factors in EnOC. A set of good-prognosis markers (PR, ER, β-catenin and vimentin) and poor-prognosis markers (p53, p16 and L1CAM) were identified. Our findings support continuation of the use of the 3-tier grading system for EnOC and provide clinically feasible IHC biomarkers for prognostic profiling.