Molecular typing of epithelial ovarian carcinomas using inflammatory markers

Ovarian epithelial carcinomas have recently been classified as slow growing type I tumors and rapidly growing highly aggressive type II tumors. The present study sought to molecularly characterize type I and II tumors using known molecular markers.

Specimens from 213 patients with ovarian carcinoma were categorized as type I or type II, and evaluated by immunohistochemistry for the inflammatory markers glucose transporter protein-1 (Glut-1), inducible nitric oxide synthase (iNOS), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and nuclear factor kappa B. Statistical analysis was performed to investigate whether these molecular markers could distinguish between type I and type II tumors. Kaplan-Meier survival curves and COX regression analysis were used to determine the prognostic effect of these markers on survival in the 2 types of tumors.

Overexpression of COX-1, COX-2, iNOS, and Glut-1 was significantly higher in type II tumors (P < .05). Women with type II tumors had a poorer median survival (60 months) as compared with those with type I tumors (141 months) (P = .0001). Multivariate analysis revealed type II tumors, late stage, and age >60 years as significant predictors of poor survival. For type II tumors, median survival of patients with tumors overexpressing COX-2 was 44 compared with 85 months for those with tumors with low COX-2 expression (P = .029). Looking at both type I and II tumors, the number of markers simultaneously overexpressed in each tumor was a significant predictor of poor patient survival (P = .005).

The present study demonstrates that the new proposed histologic classification of ovarian epithelial carcinomas correlates with a distinct expression of inflammatory pathway proteins. High expression of these markers may explain the different biologic behavior of these 2 tumor types and provide targets for therapy.