145 patients with histologically proven ISUP 4 or 5 PC [mean age 70 ± 8 y; median PSA 10.9 ng/ml (IQR 6.8–19.1 ng/ml); median PSAD 0.25 ng/ml/cm3 (IQR 0.16–0.42 ng/ml/cm3)] in either biopsy at baseline or RPE specimen were finally included. The gene discussed is KLK3; the disease is pachyonychia congenita.