KRT19 and pancreatic serous cystadenoma: The numbers of K19+ cells, NIK+ cells, and K19+NIK+ cells (NIK-expressing cholangiocytes) were considerably higher in primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), hepatitis B virus (HBV), hepatitis C virus (HCV), and alcoholic cirrhosis (Fig. 1A, B).