HMGB1 and Miyoshi myopathy: Within the nucleus, HMGB1 is a non-histone chromatin-binding protein that regulates nucleosome assembly and chromatin structure.4 HMGB1 is passively released by necrotic cells or actively secreted by immune and cancer cells.4, 5, 6, 7 When in the extracellular space, HMGB1 is responsible for the initiation and perpetuation of the inflammatory response and also directly promotes MM growth.4, 5, 7