Evolving options and future challenges for targeted therapies in ErbB2 (HER2)-positive breast cancer

This article provides an overview of the rationale and advent of targeted therapies for ErbB2-positive breast cancer. It summarizes a presentation from a symposium held at the ECCO 14 congress.The concept that oncogenic phenotype arises from several activated oncogenes but tumour growth is frequently highly dependent on a single oncogene (oncogene addiction) underlies the success of targeted cancer therapy. This has been effectively demonstrated in breast cancer, with the advent of ErbB2-targeted therapy. The first such agent used in treating patients with ErbB2-positive breast cancer, trastuzumab, heralded a major advance in this patient group. A wealth of novel targeted agents designed to further improve treatment in this setting are currently in development, including small molecule kinase inhibitors such as lapatinib, and anti-angiogenic agents that starve the growing tumour and limit metastasis.In conclusion, novel targeted therapies could further improve outcomes in patients with ErbB2-positive breast cancer beyond that seen to date.