Potential new therapeutic target for a subset of aggressive breast cancers

New therapeutic targets for metastatic breast cancer are urgently needed. A team of researchers led by Stefan Offermanns and Thomas Worzfeld, at the Max-Planck-Institute for Heart and Lung Research, Germany, has now generated data in mice and humans that suggest that the protein Plexin-B1 represents a new candidate therapeutic target to treat patients with breast cancer found to overexpress the molecule ErbB-2. ErbB-2 is overexpressed in approximately 30% of all breast cancers, and ErbB-2–overexpressing tumors have high metastatic potential and poor prognosis. The researchers found that overexpression of ErbB-2 in human breast cancer cell lines led to activation of Plexin-B1, and that this promoted human breast cancer cells to develop in vitro characteristics of metastatic cells. Offermanns, Worzfeld, and colleagues therefore suggest that blocking the ErbB-2/Plexin-B1 interaction or inhibiting Plexin-B1–mediated signaling may be a target for therapies.