To overcome these limitations, several PSA derivatives and composite indices, such as the Prostate Health Index (PHI), have been introduced and shown to improve the discrimination of clinically significant PC (csPC; Gleason ≥7 or International Society of Urological Pathology grade group ≥2) [12], [13], [14], [15], [16], [17], [18]. This evidence concerns the gene KLK3 and pachyonychia congenita.