The prognostic and predictive value of TMPRSS2-ERG gene fusion and ERG protein expression in prostate cancer biopsies.

Abstract

The clinical course of prostate carcinoma (PCa) is very heterogeneous. Consequently, a personalised approach for risk stratification and treatment planning is important. Recently, it has become evident that PCa, also at the genomic level, is heterogeneous. An early and common alteration is the gene fusion between the transmembrane protease serine 2 (TMPRSS2) gene and the v-ets avian erythroblastosis virus E26 oncogene homolog (ERG) gene resulting in expression of the oncoprotein ERG. The gene fusion is present in approximately half of PCa patients and the resultant two subgroups demonstrate marked differences in their genomic signatures. It has been hypothesised that genomic alterations can explain some of the observed heterogeneity in the clinical course of PCa. In order to conduct an analysis of the prognostic and predictive value of ERG protein expression in PCa biopsies, the thesis sought to evaluate: 1) the concordance in ERG expression between biopsies and radical prostatectomies: 2) the association between expression of ERG protein and the risk of PCa progression during active surveillance (AS), and 3) the association between ERG protein expression and response to primary castration-based treatment for advanced PCa.