Targeting HER2 as a therapeutic strategy for breast cancer

HER2 is a transmembrane receptor tyrosine kinase that mediates cell growth, differentiation and survival.

Figure 1.1 HER2 activates the signal transduction pathway to influence cell growth and survival, motility and adhesion1 (copyright © 2007 Massachusetts Medical Society. All rights reserved)

Overexpression of the HER2 protein and/or amplification of the HER2 gene occurs in approximately 25–30% of human breast cancers.^2,3 HER2 overexpression is associated with poor prognosis, indicating a more aggressive form of the disease, with faster relapse times at all disease stages and shortened survival.³ HER2, therefore, represents a key therapeutic target in the treatment of breast cancer.

The development of Herceptin, a recombinant humanised monoclonal antibody against HER2 that activates the immune system and suppresses HER2, represents a major breakthrough in the treatment of both early and metastatic HER2-positive breast cancer. Given the substantial benefits of Herceptin, no treatment decision in breast cancer should be taken without performing HER2 testing to confirm HER2 status.

REFERENCES
1. Hudis CA. N Engl J Med 2007; 357: 39-51.
2. Slamon DJ et al. Science 1987; 235: 177-182.
3. Slamon DJ et al. Science 1989; 244: 707-712.