MMP9 and bone cancer: Other in vitro and in vivo reports explain the essential mechanisms and pathways of curcumin-induced cellular apoptosis in bone cancer, namely the inhibition of nuclear factor-κβ (NF-κβ) and the expression of interleukin-6 (IL-6) and interleukin-11 (IL-11), the interference with tumor-induced angiogenesis by the downregulation of vascular endothelial growth factor and matrix metalloproteinases-9 (MMP-9) and the prevention of the expression of extracellular signal-regulated kinase [204,205,206].