CASP3 and neoplasm: Cleavage of caspase 3 is a late and irreversible event in the process of apoptosis and therefore serves as a marker for both major apoptotic pathways leading to cell death.[17] Compared to vehicle-treated, TP187-treated tumor sections showed increased cytoplasmic staining with anti-cleaved caspase 3 antibody (Fig. 2C, middle panel).