fig1

Figure 1. BORG is a potent facilitator of breast cancer metastasis. Breast cancer cells can disseminate at very early stages of development. Due to the benign microenvironment associated with these lesions, these cells are likely to harbor low levels of BORG (BORG^lo) expression and are prone to establishing dormant lesions in metastatic tissues. Nonetheless, stromal factors and environmental stressors in the metastatic microenvironment can induce BORG expression, thereby compelling these dormant cells to reinstate proliferative programs. The progression of primary tumors is associated with a hypoxic environment and stark competition for nutrients. Such stresses can enhance BORG expression in a subset of cells (BORG^hi). These BORG^hi cells can disseminate to distant tissues where they exploit the proliferative and survival advantages afforded by BORG to produce overt metastases. Cytotoxic chemotherapeutic treatment is effective against BORG^lo cells, but BORG^hi cells show resistance to such therapies and are the foundation for chemoresistant, residual disease that can eventually metastasize to distant tissues. BORG: BMP/OP-Responsive Gene