HMGB3 and leukemia: It has 80% identity with HMGB1 and HMGB2.8 The high-mobility group box (HMG-box) subfamily is a group of chromosomal proteins that are involved in DNA replication, recombination, transcription, and repair.9, -11 HMGB3 plays a critical role in leukemia stem cell renewal by activation of MLL/Hox/Meis.