BRCA2 and pachyonychia congenita: Codeletion of BRCA2 and RB1 was found in approximately 10% to 50% of PC patients, and the codeletion might be one of the resistance mechanisms in NHTs (44); the sensitivity to PARP inhibition was increased in this state, and the inhibition of PARP might have weakened the growth of mCRPC cells (44).