KLK3 and pachyonychia congenita: In this setting, PSA and PSA kinetics (i.e., PSA doubling time (PSAdt)—“which measures the exponential increase in serum PSA over time” [8] and PSA velocity (PSAvel)—an indication of the “absolute annual increase in serum PSA (ng/mL/year)” [8]) are valuable for the forecast of recurrent PC [4,9].