Expression of MMPs is increased by prostaglandin and several cytokines (including IL-1β, IL-17 (Singh et al., 2018), TNF-α, and IFN-γ) (Elkington P.T. et al., 2011); hypoxic conditions, present in TB lesions, also increase expression and secretion of MMP-1 through the induction of hypoxia-inducible factor 1α (Belton et al., 2016). Here, TNF is linked to tuberculosis.