KMT2A and acute myeloid leukemia: (2019) expanded this spectrum, revealing RARB/RARG fusions (e.g., TBL1XR1-RARB, CPSF6-RARG) and KMT2A rearrangements in morphologically similar cases, with RARA-negative patients showing inferior survival and higher relapse rates despite AML-style chemotherapy (13).