MYD88 and aneurysmal bone cyst: Although BET inhibitors are active in all ABC DLBCL cell lines, their activity is largely cytostatic with a strong induction of apoptosis limited to cell lines bearing somatic mutations in essential genes such as myeloid differentiation factor 88 (MYD88) and cluster of differentiation 79B (CD79B) [9, 10], representative of the genetically defined subclusters MCD/C5 [4–6].