The number of invaded cells decreased in the GIST882, GIST48 and the GIST‐T1 cell lines after ITGA4 siRNA transfection as compared with the control siRNAs (GIST882, mean = 3.4, standard error [S.E.] = ±1.6 versus control, mean = 29.7, S.E. = ±8.2; P = 0.014; GIST48, mean = 8.3, S.E. = ±2.9 versus control, mean = 23.2, S.E. = ±4.5, P = 0.016; and GIST‐T1, mean = 1.5, S.E. = ±1.1 versus control, mean = 17.4, S.E. = ±5.1, P < 0.001; Fig. 4). This evidence concerns the gene ITGA4 and gastrointestinal stromal tumor.