Moreover, BETd-260 treatment also triggered PARP-1 cleavage, which was validated by IHC assays showing that a large amount of cells were positive for cleaved PARP-1 in BETd-260-treated tumors, but not in the control tumors, suggesting that BETd-260 treatment resulted in massive apoptosis in OS tumor tissue (Fig. 5a, b). The gene discussed is PARP1; the disease is neoplasm.