[Prostate cancer: the revolution of the fusion genes]

TMPRSS2-ETS fusion gene rearrangements constitute a very common and specific alteration in prostate cancer cells. These genetic alterations lead the overexpression of ETS genes which encode the E26 family of transcription factors involved in cell proliferation. Of this family, the ERG oncogene is overexpressed in almost 50% of prostate cancer cases.

TMPRSS2-ERG overexpresses ERG through an androgen-mediated response. Structurally, the rearrangement is due to interstitial deletion and to a lesser extent to reciprocal translocation and plays a key role in cellular metabolism. Almost all fusion gene transcripts produce a truncated ERG protein and the presence of a specific isoform of this gene suggests the clonality of the tumor; hence, metastasis shares the fusion gene status of their primary lesion. Although the prognostic implications of TMPRSS2-ERG have not been fully elucidated, they constitutes a field of great diagnostic potential and, therefore, the development of techniques to identify and to analyze the presence and characteristics of this gene in a non-invasive fashion deserves great interest in this area. Currently, there is evidence supporting the hypothesis that the presence of fusion gene differentiates two molecular groups within prostate cancer with a differential behaviour making the fusion gene a potential therapeutic target. In this regard, the use of anti-HDAC (trichostatin), antagonists of estrogen receptor alpha and abiraterone acetate have shown promising results.

This review describes the great potential offered by the investigation of fusion genes in PC and the need for further studies.