DDR1 and Hepatic fibrosis: Interestingly, the extracellular domain of DDR1 can be cleaved by membrane bound matrix metalloproteinases (Fu et al., 2013) and analysis of serum levels of cleaved DDR1 in subjects affected by liver fibrosis or cirrhosis showed that levels of cleaved DDR1 represented a powerful diagnostic tool and an accurate biomarker that associates with the severity of liver fibrosis (Zhang et al., 2021).