These include commercial tests based on gene expression measurements, such as the “Prolaris” test that stratifies risk of PC progression based on a 46-gene expression signature [10], and the “MiProstate Score” that estimates the likelihood of aggressive PC by combining urinary measurements of PCA3 and TMPRSS2-ERG transcripts with serum PSA levels [11]. This evidence concerns the gene KLK3 and pachyonychia congenita.