FNDC5 and ocular melanoma: To validate our speculation whether and how circ_AFF4 and FNDC5/Irisin interactively regulated osteogenic differentiation, we cultured BM-MSCs which were transfected with circ_AFF4 and si-FNDC5 or si-NC in OM for 14 days and evaluated the osteogenesis capacity by ARS and ALP staining.