Nutlin-3, an MDM2 inhibitor, has shown selectively growth inhibitory and little cytotoxic activity in WT p53 GIST cell lines (GIST430, GIST48, GIST48B) compared with p53 mutated cells (GIST882, GIST-T1) (33). The gene discussed is MDM2; the disease is gastrointestinal stromal tumor.