CASP3 and gastrointestinal stromal tumor: Indeed, increased expression of apoptosis markers (i.e., cleaved forms of PARP and caspase-3) was observed in IM-resistant GIST T-1R cells treated with a combination of BGJ 398 (pan-FGFR inhibitor) and VEGFR inhibitors (sunitinib and regorafenib) used at subtoxic (0.5 μM) concentrations (Figure 5).