DDR2 and Hepatic fibrosis: 1995; Poudel et al. 2015). It is possible that an imbalance in the degradation of collagen would result in an upregulation of these pathways to increase production of MMPs in their inactive form. While there is no evidence yet supporting a role for DDR2 in pleural fibrosis, involvement in lung fibrosis has been demonstrated and a loss of DDR2 results in promotion of hepatic fibrosis (Olaso et al. 2011; Yang et al. 2013).