In fact, RAS(G12D) failed to induce downstream ERK1/2 phosphorylation in 3 different T-ALL cell lines as measured by either western blot or flow cytometry assay (S8A and S8B Fig), implying that the RAS/RAF/MEK/ERK pathway is not readily activated in these contexts. This evidence concerns the gene MAPK3 and acute lymphoblastic leukemia.