UCSF is doing some cutting edge research regarding the role between the HER2 and HER3 proteins and the interactions between the two. According to the article on page 3 of the Fall Newsletter (link below), HER2 cannot cause breast cancer without the help of HER3 and research at UCSF is re-defining the causative driver of this disease as the HER2-HER3 dimer, not just HER2. This is why I am SO excited about targeted therapies like Neratinib, which I understand targets HER2 and HER3. Hurry, please.
http://www.ucsfbreastcarecenter.org/aboutindex5.html