Differential expression of E-cadherin in ductal and lobular breast carcinomas and its biologic and diagnostic value

ABSTRACT

E-cadherin is a calcium dependent epithelial cell adhesion molecule. Loss of E-cadherin function has been associated with aggressive behavior in various malignancies. In this study, we analyzed the pattern of E-cadherin expression in 25 invasive carcinomas [15 ductal and 10 lobular] and 14 in slat carcinomas [10 ductal and 4 lobular] to determine its role in the morphogenesis of breast carcinoma. E-cadherin was Semiquantitatively evaluated on paraffin-embedded tumor tissue by immunohistochemistry. Our results proved a highly significant correlation of E-cadherin membrane expression with the histologic phenotype of the tumor. While preserved [strong] to reduced membrane expression was seen in all invasive and in situ ductal carcinomas as in normal mammary epithelium, 90% [9/10] of invasive lobular carcinoma [ILC] and 75% [3/4] of lobular carcinoma in situ [LCIS] cases showed complete loss of E-cadherin expression. The only E-cadherin positive ILC case was diagnosed histologically as pleomorphic variant and was associated with solid ductal carcinoma in situ [DCIS] component. This tumor most probably represents an example of invasive ductal carcinoma [IDC]. Reduced E-cadherin expression increased significantly from DCIS [20%] to IDC [66.7%]. A highly significant difference between E-cadherin expression in IDC and ILC [P = 0.0001] and a significant difference between DCIS and LCIS [P = 0.004] were found. So we concluded that in tumors with histologically equivocal features, immunohistochemical detection of E-cadherin expression can be a useful diagnostic tool for differentiation of the ductal and lobular carcinomas of the breast