RBBP4 and neoplasm: Retinoblastoma-binding protein 4 (RBBP4/RbAp48), also known as histone-binding protein RBBP4, is a 48 kDa tumor-specific/oncogenic protein involved in transcription regulatory complexes that control cell cycle gene expression [18], proliferation, migration, invasion, and apoptosis, playing an important role in chromatin metabolism, nucleosome assembly, and histone modification [17,20].