SEZ6 and cholangiocarcinoma: Both DLL3 and SEZ6 were negative with only focal weak positivity for DLL3 in three tumors, a poorly differentiated colonic adenocarcinoma, a multifocal moderately to poorly differentiated hepatocellular carcinoma, and a moderately differentiated cholangiocarcinoma with weak to strong expression in 10 to 30% of the tumor cells (H-score ranging from 20 to 50; average 30).