A New Rabbit Monoclonal E-Cadherin Antibody Shows Higher Sensitivity Than Mouse Monoclonal E-Cadherin [HECD-1] Antibody in Infiltrating Ductal Cell Carcinomas
Laura Hoang, Ryan Bremer, Ping Tang, David G Hicks, Thomas Haas, David Tacha. Biocare Medical, LLC, Concord, CA; University of Rochester Medical Center, Rochester, NY; Mercy Health System, Janesville, WI
Background: The loss of E-cadherin expression has been observed in breast cancer and is associated with a poor prognosis. Immunohistochemical studies have shown E-cadherin to be expressed in breast ductal carcinoma with loss of expression in lobular carcinoma. As a result, mouse monoclonal anti-E-cadherin [HECD-1] has been used by pathologists to differentiate between ductal and lobular carcinomas of the breast, with currently published sensitivity and specificity of approximately 90%. Rabbit monoclonal antibodies may combine the best properties of both mouse monoclonal antibodies and rabbit antisera. This study compared the staining sensitivity of a new rabbit monoclonal E-cadherin vs. mouse monoclonal clone HECD-1. The two E-cadherin antibodies were further applied in the discrimination of ductal from lobular carcinomas, in combination with a p120 catenin antibody.
Design: Rabbit monoclonal E-cadherin and HECD-1 were tittered and optimized for immunohistochemical staining in infiltrating ductal breast cancers using an HRP-polymer detection system and visualization with DAB. 31 cases of infiltrating ductal cell carcinoma and 29 cases of lobular carcinoma were evaluated. A semi-quantitative scoring system for intensity of membrane staining with E-cadherin was applied: 0=negative, 1=weak to medium, 2=medium to strong, 3=strong and intensely strong.
Results: The rabbit monoclonal anti-E-cadherin antibody showed much sharper staining and increased sensitivity (30/31, 97%) compared to mouse monoclonal HECD-1 (27/31, 87%) [Table 1]. No staining was observed in any of the lobular carcinomas evaluated. All lobular carcinomas were confirmed by the absence of E-cadherin and the diffuse cytoplasmic expression of p120 catenin.
|Antibody||Score 0||Score 1||Score 2||Score 3||Average score||Positive (n=31)||% Positive|
|Mouse E-cadherin (HECD-1)||4||10||15||2||1.5||27||87%|