TMPRSS2 and pachyonychia congenita: More than half of primary PC patients (up to 70%) show formation of the chimeric oncogene TMPRSS2-ERG—a product of fusion of the 5’-untranslated region of androgen-regulated gene TMPRSS2 (chr21q22.2) with the ETS family of transcription factors genes, namely ERG (chr21q22.3), which results in aberrant expression of ERG [14,15,16,17].