DDR2 and primary biliary cholangitis: DDR2 mRNA is markedly up-regulated in cirrhotic livers. DDR2 mRNA expression is detected in all small bile duct epithelial cells and fibroblasts/stromal cells within fibrotic regions from PBC or PSC, but not the large bile ducts. However, DDR2 mRNA is confined to fibrotic lesions, but not the entire biliary epithelium in cirrhotic livers from ALD or HCV