Rearrangements of ERG and the androgen-regulated gene transmembrane serine protease 2 (TMPRSS2) are prevalent in a large percentage of prostate cancers, where the TMPRSS2-ERG fusion has been shown to correlate with prostate cancer-specific death and metastasis in men managed with expectant therapy of localized prostate cancer [19]. The gene discussed is TMPRSS2; the disease is prostate carcinoma.