KDR and neoplasm: While another IHC-based study showed that Ang2, Tie2, and VEGFR2 expression show positive correlation with the CRC tumor marker carcinoembryonic antigen (CEA) and microvascular density (MVD), Ang2, but not Tie2 or VEGFR2 levels, correlates with the carbohydrate antigen19-9 (CA 19-9) CRC tumor marker [60].