CDKN2A and pachyonychia congenita: It has been demonstrated that germline mutations in ATM Serine/threonine kinase (ATM), breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2), serine/threonine kinase 11 (STK11), Cationic trypsinogen-gene (PRSS1), partner and localizer of BRCA2 (PALB2), p16/cyclin dependent kinase inhibitor 2A (CDKN2A), and the mismatch repair genes (MLH1, etc.)increase the risk of PC [160–162].