Effect of ATRA on cell proliferation of GIST-T1, GIST-882 and human normal fibroblast WI-38 cells. GIST-T1, GIST-882 and human normal fibroblast WI-38 cells at a density of 1 × 105 cells/ml were treated with different concentrations of ATRA dissolved in DMSO or with DMSO alone (0 μM ATRA as control) for 3 days. Panel A shows cell growth curve which represents the effect of different concentrations of ATRA. Results were calculated as the percentage of the control values. Panel B shows the effect of ATRA on adherence of GIST-T1 cells at various concentrations of ATRA. Panel C shows cell morphologic change of GIST-T1 cells after 3-day treatment with 180 μM ATRA.