E-cadherin mRNA expression in breast carcinomas correlates with overall and disease-free survival.

E-cadherin (Epithelial-cadherin) is a subclass of the cadherin family that plays a major role in the maintenance of intercellular junctions in epithelial tissues. E-cadherin is also involved in the interactions between epithelial cells and T lymphocytes. In order to explore the relationship between E-cadherin expression, cancer invasion and metastases in vivo, we estimated its expression in normal breast specimens, fibroadenomas, cystic samples and primary breast carcinomas using a semiquantitative reverse transcription-polymerase chain reaction. The relationship between E-cadherin expression, survival and disease-free survival was also investigated. In comparison with normal breasts, 70% of the primary tumors showed reduced expression of E-cadherin suggesting that downregulation of this cell adhesion molecule is a common event in breast carcinoma. Significant correlation was found between E-cadherin expression and the histological classification. Most of the advanced tumors grades (10/13 tumors with grade III) presented decreased E-cadherin expression. No correlation was found between E-cadherin expression, estrogen and progesteron receptors, age and menopausal status at diagnosis. However, disease-free and overall survival was associated with E-cadherin expression. Patients showing poorly expressed E-cadherin in tumor tissue had a worse prognosis. The same results were observed for women without lymph node invasion or metastasis at diagnosis even when they were grouped according to their histological grade for statistical analysis. Therefore, E-cadherin mRNA expression in invasive breast carcinomas might be an early prognostic factor of metastasis.