Emergence of ETS transcription factors as diagnostic tools and therapeutic targets in prostate cancer.

The discovery of chromosomal translocations in prostate cancer has greatly enhanced our understanding of prostate cancer biology. Genomic rearrangements involving the ETS family of transcription factors are estimated to be present in 50-70% of prostate cancer cases. These rearrangements fuse the ETS factors with promoters of genes that are androgen regulated. Thus, the expression of ETS factors, such as ERG, ETV1, ETV4 and ETV5, is mediated by androgen. In-vitro and in-vivo studies suggest that overexpression of ETS proteins increase cell proliferation and confer an invasive phenotype to prostate cancer cells. Epidemiological studies demonstrate that ETS-fusion positive patients exhibit tumors corresponding to a more advanced disease. The ability of ETS factors to serve as markers for screening and diagnosing prostate cancer patients is being investigated, and the results have been largely positive to date. Additionally, ETS factors present an excellent opportunity as therapeutic targets and several strategies have been devised to directly target ETS proteins or their binding partners and downstream effectors.