Using Protein Microarray Technology to Screen Anti‐E‐Cadherin (ECAD) Monoclonal Antibodies for Specificity and Applications in Pathology

Abstract

E‐cadherin (ECAD) is a calcium‐dependent cell‐cell adhesion molecule playing a crucial role in establishing epithelial architecture and maintaining cell polarity and differentiation. Reports showed that decreased ECAD expression has been associated with more advanced tumor stage and grade for lung tumors, gastric tumors, breast tumors and etc. Other research discovered that staining for ECAD may be useful for the differentiation between ductal and lobular breast carcinomas. Thus, a high quality monoclonal antibody validated for immunohistochemistry (IHC) is required to evaluate ECAD protein levels in formalin‐fixed paraffin‐embedded tissue samples.To develop the a suitable monoclonal antibody for ECAD IHC analysis, 49 monoclonal antibodies were generated, of which 10 were selected for screening in IHC on breast and prostate cancer tissues. Further evaluation with a high density protein microarray chip containing 17,000 human proteins indicated that clone 3C11 is highly specific and only detected ECAD. Comparison to the monoclonal 4A2C7, showed that 3C11 is more sensitive on breast, prostate, and prostate cancer tissues. The new monoclonal antibody 3C11 will be a promising candidate to detect the expression and aberrant alterations of ECAD for the diagnosis, prognosis, and therapy of cancer.