Immunocytochemical expression of E-cadherin on fine-needle aspirates from breast carcinomas correlate with the cell dissociation pattern seen on smears

Altered E‐cadherin expression has been suggested to be of prognostic significance in breast cancers and to correlate with tumor subtype and grade. A dysfunctional, intercellular adhesion system may be responsible for the tumor cell dissociation pattern seen on fine‐needle aspirate cytology (FNAC). The aim of our study was to determine E‐cadherin expression on direct FNAC smears from breast carcinomas and compare the results with the dyscohesion grade of the tumor cells and the cytological grading. The material consisted of FNAs from 56 breast carcinomas. The degree of cellular cohesion was estimated semiquantitatively. Full expression of E‐cadherin was defined as a complete and strong membrane staining of virtually all tumor cells. All nonductal as well as 85% of the invasive ductal carcinomas revealed reduced expression or negativity for E‐cadherin. In all, 25% of carcinomas with dyscohesion Grade 1 (mainly in groups) revealed full expression of E‐cadherin, in contrast to 12.5% of tumors with dyscohesion Grade 3 (mainly dispersed cells). Nuclear positivity was seen in 21% of the tumors (12 cases) and seven of these were G3 ductal carcinomas. In conclusion, E‐cadherin expression correlated with the cell dissociation pattern seen on direct smears from FNAC of breast carcinomas, but is only one of several markers that modulate this pattern. High‐grade carcinomas rarely revealed full expression and had a high incidence of aberrant nuclear localization of E‐cadherin. Diagn. Cytopathol. 25:382–388, 2001. © 2001 Wiley‐Liss, Inc.