CASP3 and neoplasm: Neither drug had a significant effect on activated Caspase-3 positivity alone at this time point, but the combination of APX2009 and FC12-531A significantly increased the proportion of remaining cells that were positive for activated Caspase-3 from 0.3% in DMSO to 0.9% (p < 0.01) (Figs 5G and S1H), providing confirmation that the observed decrease in tumor cell number/density with this combination treatment strategy is at least partially due to cell killing.