Adaptive Immune Responses and HER2/neu-Positive Breast Cancer

Oncogenic signaling, such as HER2/neu signaling, has been shown to play a major role in tumorigenesis in a subset of breast cancer patients. The use of anti-HER2/neu antibody has not only revealed the mechanisms for HER2/neu signaling, but has also shown a therapeutic advantage of its blockade. The use of trastuzumab has greatly improved the treatment of HER2-positive breast cancer. Although this therapy has been used in the clinic for over 20 years, recent data are still uncovering new mechanisms by which this antibody exerts its antitumor activity. In addition to improved understanding of the molecular mechanisms by which this therapy inhibits growth of tumor cells, it has been discovered that anti-HE2/neu therapy initiates and requires the adaptive immune system. The presence of anti-HER2/neu-initiated adaptive immunity gives credence to efforts targeted at stimulating the immune system in treating HER2-positive breast cancer. This review focuses on the role of the inflammatory response in HER2-positive breast cancer with particular emphasis on trastuzumab therapy.