To assess the in vitro expression of apoptotic and anti-apoptotic proteins in GIST, we treated the GIST882, sensitive to imatinib, and imatinib-resistant GIST48B and GIST62 GIST cell lines with OPN at different concentrations and analyzed the protein expression of specific apoptosis-related proteins by western blotting. Here, SPP1 is linked to gastrointestinal stromal tumor.