Novel molecular subtypes of serous and endometrioid ovarian cancer linked to clinical outcome

作者:Tothill Richard W; Tinker Anna V; George Joshy; Brown Robert; Fox Stephen B; Lade Stephen; Johnson Daryl S; Trivett Melanie K; Etemadmoghadam Dariush; Locandro Bianca; Traficante Nadia; Fereday Sian; Hung Jillian A; Chiew Yoke Eng; Haviv Lzhak; Gertig Dorota; deFazio Anna; Bowtel David D L*
来源:Clinical Cancer Research, 2008, 14(16): 5198-5208.
DOI:10.1158/1078-0432.CCR-08-0196

摘要

Purpose: The study aim to identify novel molecular subtypes of ovarian cancer by gene expression profiling with linkage to clinical and pathologic features. Experimental Design: Microarray gene expression profiling was done on 285 serous and endometrioid tumors of the ovary, peritoneum, and fallopian tube. K-means clustering was applied to identify robust molecular subtypes. Statistical analysis identified differentially expressed genes, pathways, and gene ontologies. Laser capture microdissection, pathology review, and immunohistochemistry validated the array-based findings. Patient survival within k-means groups was evaluated using Cox proportional hazards models. Class prediction validated k-means groups in an independent dataset. A semisupervised survival analysis of the array data was used to compare against unsupervised clustering results. Results: Optimal clustering of array data identified six molecular subtypes. Two subtypes represented predominantly serous low malignant potential and low-grade endometrioid subtypes, respectively. The remaining four subtypes represented higher grade and advanced stage cancers of serous and endometrioid morphology. A novel subtype of high-grade serous cancers reflected a mesenchymal cell type, characterized by overexpression of N-cadherin and P-cadherin and low expression of differentiation markers, including CA125 and MUC1. A poor prognosis subtype was defined by a reactive stroma gene expression signature, correlating with extensive desmoplasia in such samples. A similar poor prognosis signature could be found using a semisupervised analysis. Each subtype displayed distinct levels and patterns of immune cell infiltration. Class prediction identified similar subtypes in an independent ovarian dataset with similar prognostic trends. Conclusion: Gene expression profiling identified molecular subtypes of ovarian cancer of biological and clinical importance.