CASP3 and neoplasm: On the other hand, Lu et al. demonstrated that MSC had an inhibitory effect on mouse tumor cells and ascitogenic hepatoma cells in a cell-dependent manner involving Caspase 3, an apoptotic protein, and p21, a negative regulator of cell cycle, implying that MSC exert tumor inhibitory effects in the absence of host immunosuppression, by inducing G0/G1 phase arrest and apoptosis of cancer cells [120].