In cancer studies, miR-551b directly suppresses cyclin D1 (a key cell cycle regulator) by binding to its mRNA 3‘UTR, thereby inhibiting cell proliferation.53,54 This mechanism may extend to osteoblasts, where miR-551b could modulate osteogenic precursor cell proliferation by downregulating cyclin D1, thereby fine-tuning bone matrix synthesis. The gene discussed is CCND1; the disease is cancer.