SOX9 and primary biliary cholangitis: In chronic biliary diseases such as primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC), DRs are prominent and composed mostly of cells expressing biliary (Cytokeratins 7 and 19), neuroendocrine (NCAM, Chromogranin A), and stem cell markers (Sox9, CD133) [50, 59].