Abstract
The ability to probe diseases at the genomic level has improved our understanding and enhanced the treatment of breast cancer. One important finding relates to the HER2 oncogene which encodes a novel transmembrane receptor that, when overexpressed, appears to confer growth and survival advantages to breast tumor cells. This fortuitous discovery enabled researchers to develop agents which could inhibit receptor-mediated tumor cell signaling. Numerous clinical trials of such agents have demonstrated improved outcomes in patients with HER2-positive breast cancer. Nonetheless, not all tumors respond to therapy targeting the receptor, while relapses occur after an initial response to treatment. This paper provides a historical and current perspective of the treatment of patients with HER2-positive breast cancer.