Background: The maintenance of adult tissue architecture largely depends on structural and functional integrity of cadherins, a superfamily of Ca2+-dependent cell-cell adhesion molecules that usually mediate homophilic and homotypic intercellular adhesion. P-cadherin is expressed by myoepithelial cells of normal breast tissue, and is aberrantly expressed in a subset of breast carcinomas. In addition, recent studies have demonstrated that the expression of this protein in breast cancer is significantly correlated with high histological grade and negativity for estrogen receptors (ER). Objectives: To investigate the expression of P-cadherin and ER in invasive breast carcinomas and correlate the obtained results. Material and methods: The expression pattern of P-cadherin and ER was immunohistochemically studied in 149 invasive carcinomas of the breast; subsequently, the statistic correlation between ER and P-cadherin immunophenotypes was assessed. Results: P-cadherin was detected in myoepithelial cells of normal breast tissue and in 46 out of 146 (31.5%) cases of invasive breast carcinomas. P-cadherin expression showed a high inverse correlation with ER expression, and it was observed that the subset of P-cadherin positive and ER negative tumours were related to higher histological grade and more agressive behaviour. Conclusion: We demonstrated that P-cadherin identifies a subgroup of breast carcinomas, which lacks ER expression, and that seems to represent an advanced step of cancer progression. Our data suggests the hypothesis that an alternative estrogen independent pathway regulates P-cadherin expression.
P-cadherin Estrogen receptor; Invasive breast carcinomas
