Therefore, in hydroxytyrosol treated melanoma cells we report a dose-dependent induction of the intrinsic apoptotic pathway through the activation of pro-apoptotic proteins such as p53 and caspases-9 and -3, the down regulation of survival proteins such as PARP and AKT, the increased expression of γH2AX protein, as well as the inhibition of cell colony formation. The gene discussed is PARP1; the disease is melanoma.