PARP1 and small cell lung carcinoma: Cleaved PARP was also increased following treatment with BKM-120 (p = 0.01), suggesting that, unlike with the PARP inhibitor, which is believed to elicit a majority of its cytotoxic effect through PARP trapping [26], BKM-120 kills SCLC cells through apoptosis, which has been reported elsewhere as the primary mode of cell killing by BKM-120 [39].