E-Cadherin as a diagnostic biomarker in breast cancer

BACKGROUND: E-cadherin is expressed in most normal epithelial tissues. Selective loss of E-cadherin can cause dedifferentiation and invasiveness in human carcinomas, leading E-cadherin to be classified as a tumor suppressor. Loss of E-cadherin has been demonstrated in invasive lobular carcinoma of the breast, but the relationship between E-cadherin expression and breast cancer histopathology and prognosis is less clear. AIM: Our objective was to assess loss of E-cadherin as a diagnostic breast cancer biomarker and as an aid to the sub-classification of invasive breast cancer. We also correlated the loss of expression of E-cadherin with various clinical and pathologic prognostic factors. MATERIAL AND METHODS: Breast cancer specimens after modified radical mastectomy were obtained from women who underwent surgery at Grant Medical College and Sir J.J Group of Hospitals, Mumbai, India between May 2007 and October 2010. We stained 276 breast cancers specimens with monoclonal antibodies to E-cadherin. The breast cancers were classified by histopathological type. RESULTS: A statistical correlation of E-cadherin loss with a positive diagnosis of invasive lobular carcinoma was found, but there was no correlation with any prognostic tumor variables. A negative E-cadherin stain was a sensitive and specific biomarker to confirm the diagnosis of invasive lobular carcinoma (specificity 97.7%; negative predictive value 96.8%; sensitivity 88.1%; and positive predictive value 91.2%). Positive E-cadherin expression was also associated with tubulolobular carcinomas. CONCLUSIONS: E-cadherin immunohistochemistry is helpful in classifying breast cancer cases with indeterminate histopathologic features. E-cadherin loss is uncommon in non-lobular carcinomas but shows no correlation to currently established prognostic variables.