COX-2 expression in lobular in situ neoplasia of the breast: correlation with histopathological grading system according to the Tavassoli classification.
By immunocytochemistry, Western blotting and flow cytometry analysis, oestrogen treatment of R2d cells was found to induce many important effects related to breast carcinogenesis, namely: (i) the emergence of a subpopulation of cells expressing CD44+/high/CD24-/low breast tumour stem cell markers; (ii) the induction of EMT (epithelial-to-mesenchymal transition); (iii) the acquisition of metastatic ability; and (iv) the expression of COX-2 (cyclo-oxygenase-2) through a CD44-mediated mechanism.
These data suggest that downregulation of RhoGDI could be a critical mechanism of breast tumor development, which may involve the hyperactivation of Rho GTPases and upregulation of COX-2 activity.