CASP3 and neoplasm: Western blotting experiments confirmed that cleaved PARP expression, the active form involved in the apoptotic process, increased in concomitance with crizotinib concentration (1.5 μM and 5 μM) in both ARMS tumour cell lines, whilst cleaved caspase-3 levels were evident only in 5 μM crizotinib-treated cells (Fig. 4d).