Four patients with Ik6 were positive for gene fusions: BCR-ABL1 (2/4 patients) ETV6-RUNX1 (1/12 patients) and E2A-PBX1 (1/5 patients); the remaining Ik6 positive cases did not have any of the characteristic ALL gene fusions. The gene discussed is RUNX1; the disease is acute lymphoblastic leukemia.