T‐cell acute lymphoblastic leukemia (ALL)/lymphoma is an uncommon disease in adults and more aggressive than the more common pediatric counterpart.1 T‐ALL in adults, however, is potentially curable with 50% of 5‐year survival rate.2 Chromosomal translocations occur in a subset T‐ALL cases; these translocations often involve the T‐cell receptor gene loci or KMT2A with variable partner genes, including TAL1, TAL2, TLX1, TLX3, HOXA, LMO1, LMO2, and NKX2. 3, 4, 5, 6, 7 Several genes involving various cellular signaling pathways are also recurrently mutated in T‐ALL. The gene discussed is KMT2A; the disease is acute lymphoblastic leukemia.