MMP9 and melanoma: Besides, Zhu et al. has provided evidence that TNFα stimulates the migratory potential of melanoma cells via the upregulation of fibronectin and integrin expressions, counteracting the suppressive effect of α-MSH.342,343 Consistent with this, TNFα promotes the expression of MMP2 and MMP9 to facilitate tumor cell migration.344,345 More importantly, it has been revealed that TNFα determines the phenotypic plasticity of melanoma cells by antagonizing MITF expression via downstream c-Jun.