BRCA1 and pachyonychia congenita: As best-in-class examples, PARP inhibitors targeting germline BRCA1 or BRCA2 mutations [44], TRK inhibitors for NTRK1, NTRK2, or NTRK3 fusions [45], and immune checkpoint inhibitors for tumors with DNA mismatch repair (MMR)-deficiency or high microsatellite instability (MSI-H) [46] have been approved in PC.