title: Aberrant E-cadherin staining patterns in invasive mammary carcinoma.
abstract: BACKGROUND
  E-cadherin, a cell surface protein involved in cell adhesion, is present in normal breast epithelium, benign breast lesions, and in breast carcinoma. Alterations in the gene CDH1 on chromosome 16q22 are associated with changes in E-cadherin protein expression and function. Inactivation of E-cadherin in lobular carcinomas and certain diffuse gastric carcinomas may play a role in the dispersed, discohesive "single cell" growth patterns seen in these tumors. The molecular "signature" of mammary lobular carcinomas is the loss of E-cadherin protein expression as evidenced by immunohistochemistry, whereas ductal carcinomas are typically E-cadherin positive.
  
  
  METHODS
  We report on E-cadherin immunostaining patterns in five cases of invasive mammary carcinoma.
  
  
  RESULTS
  These were five exceptional instances in which the E-cadherin immunophenotype did not correspond to the apparent histologic classification of the lesion. These cases which are exceedingly rare in our experience are the subject of this report.
  
  
  CONCLUSIONS
  Findings such as those illustrated in this study occur in virtually all biologic phenomena and they do not invalidate the very high degree of correlation between the expression of E-cadherin and the classification of breast carcinomas as ductal or lobular type on the basis of conventional histologic criteria.
authors.affiliation: Department of Pathology and Laboratory Medicine, New York Presbyterian Hospital Weill Cornell Medical Center, New York, NY, USA. malini672001@yahoo.com
authors.forename: Malini
authors.initials: M
authors.lastname: Harigopal
authors.forename: Sandra J
authors.initials: SJ
authors.lastname: Shin
authors.forename: Melissa P
authors.initials: MP
authors.lastname: Murray
authors.forename: Satish K
authors.initials: SK
authors.lastname: Tickoo
authors.forename: Edi
authors.initials: E
authors.lastname: Brogi
authors.forename: Paul Peter
authors.initials: PP
authors.lastname: Rosen