In general, PARP inhibitor monotherapy (e.g., olaparib, rucaparib, niraparib, and pamiparib) is most therapeutically effective in maintenance settings for tumors (e.g., breast and ovarian cancer) with BRCA mutations or homologous recombination deficiency [23]. Here, PARP1 is linked to hyperinsulinemic hypoglycemia, familial, 4.