The WL5 antibody is an anti-colorectal cancer antibody secreted by the WL5 hybridoma clone. Flow cytometric analysis showed that WL5 specifically binds to the HT29 and LS180 colorectal cancer cell lines. Immunohistochemical analysis performed on a tissue microarray demonstrated that the WL5 antibody can be used for the specific and sensitive diagnosis of colorectal carcinoma. Furthermore, WL5 mediated antibody dependent cell-mediated cytotoxicity (ADCC) of tumor cells and exhibited similar antitumor activity to adriamycin (ADM) but avoided the cardiomyopathy and decrease in peripheral white blood cell counts associated with prolonged ADM treatment. The glycoprotein, carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), was identified as the target antigen of WL5 through immunoprecipitation and mass spectrometric analyses, which might provide a potential biomarker and therapeutic target for colorectal cancer. (C) 2013 Elsevier Inc. All rights reserved.