The IC50 of selumetinib in four t(17;19)‐ALL cell lines (two cell lines with KRAS mutation and two cell lines without it) (median: 100 μmol/L) was almost identical to that in 16 t(1;19)‐ALL cell lines (four cell lines with KRAS mutation and 12 cell lines without it) (97 μmol/L). This evidence concerns the gene KRAS and acute lymphoblastic leukemia.