To confirm, we performed ChIP-PCR assays on RS4;11 and SEM, human MLL-AF4 translocated B-ALL cell lines, and determined that the first intron of IGF2BP3 is strongly bound by MLL-AF4 (Fig. 1b; Supplementary Fig. 1c). The gene discussed is IGF2BP3; the disease is acute lymphoblastic leukemia.