Furthermore, DNA repair defects extended beyond germline variations in BRCA1/2 genes and included other genes that contribute to the DDR signature, such as germline and somatic mutations in PALB2 and somatic mutations in BRCA1, BRCA2, ATM, RPA1, REV3L, XRCC4 and XRCC. According to these findings, approximately 24% of PC patients express putative biomarkers of DDR deficiency, and thus, show potential sensitivity to DNA damaging agents; this is a significantly larger group of patients than the currently approved use of olaparib for patients with germline pathogenic variants in BRCA1/2 [3,22]. The gene discussed is BRCA1; the disease is pachyonychia congenita.