Evaluation of Mena isoforms as a surrogate for epithelial mesenchymal transformation and erlotinib resistance in breast carcinoma

1078 Background: Epithelial to mesenchymal transition (EMT) is an important step in invasiveness and has been shown to correlate with metastatic potential in several cancer cell lines, including breast carcinoma. However, given the heterogeneity of tumors in vivo, EMT has not been a reliable marker of metastatic potential in cancer patients. Mena, a member of the enabled (ena)/vasodilator-stimulated phophoprotein (VASP) family, which controls cell motility, is upregulated in the invasive subpopulation of breast cancer cells. Mena is alternatively spliced to include one of four exons: +, ++, invasive (INV), or 11a. In the presence of MenaINV, tumor cells are able to invade even at epidermal growth factor (EGF) concentrations that would otherwise be undetectable by the tumor cells. Currently, there are several clinical and genetic characteristics which can predict sensitivity to erlotinib, an EGF receptor inhibitor, but further studies are necessary. Methods: The animal models used were the polyoma middle T...