FGF2 and gastrointestinal stromal tumor: To test the ability of FGF2 to reduce GIST sensitivity to topoisomerase II inhibitors (e.g., doxorubicin and etoposide), MTS-based assay was performed for GIST cells cultured with 8 different concentrations of topoisomerase II inhibitors indicated above in the absence (control) or presence of FGF-2 (20 ng/mL).