CASP8 and neoplasm: In that context and due to the potential of GP inducing a cytotoxic effect on SCL-1 carcinoma cells and not on NHEK, apoptosis markers such as the activity of the initiator caspases 8 and 9, the executioner caspases 3 and 7, and poly (ADP-ribose) polymerase (PARP) cleavage were studied after treating the tumor cells with 2.5 and 5 μM GP or 20 μM staurosporine (Sts) as positive control (Fig. 8).