Cooperativity of TMPRSS2-ERG with PI3-kinase pathway activation in prostate oncogenesis

Abstract

Charles Sawyers and colleagues report that mice expressing a TMPRSS2-ERG fusion develop prostatic intraepithelial neoplasia, but only in the context of PI3-kinase pathway activation mediated by either Pten loss or Akt activation. They also find that human TMPRSS2-ERG–positive tumors are enriched for PTEN loss, suggesting that these two events cooperate in human prostate tumorigenesis. The TMPRSS2-ERG fusion, present in approximately 50% of prostate cancers, is less common in prostatic intraepithelial neoplasia (PIN), raising questions about whether TMPRSS2-ERG contributes to disease initiation. We identified the translational start site of a common TMPRSS2-ERG fusion and showed that transgenic TMPRSS2-ERG mice develop PIN, but only in the context of PI3-kinase pathway activation. TMPRSS2-ERG–positive human tumors are also enriched for PTEN loss, suggesting cooperation in prostate tumorigenesis.