Given the above premises, we decided to examine a series of samples from 60 consecutive cases of PC (from February 2019 to September 2020) analyzed for BRCA1/2 status, and to broaden the analysis by including 24 other cancer susceptibility genes (ABRAXAS1, ATM, APC, BARD1, BRIP1, CDH1, CHEK2, EPCAM, MLH1, MRE11, MSH2, MSH6, MUTYH, NBN, PALB2, PIK3CA, PMS2, PTEN, RAD50, RAD51C, RAD51D, STK11, TP53, XRCC2). This evidence concerns the gene STK11 and pachyonychia congenita.