TMPRSS2 and Familial prostate cancer: The most prevalent genetic rearrangement in prostate cancer involves the fusion of the androgen-regulated gene TMPRSS2 with the ETS transcription factor ERG, which is estimated to occur in ~50% of prostate cancer cases (Tomlins et al., 2005; Kumar-Sinha et al., 2008) being by far the single most common genetic fusion gene in solid tumors (PCAWG Transcriptome Core Group et al., 2020).