Targeting HER receptors in cancer

Receptor tyrosine kinases play important roles in animal development and their deregulation has been linked to several pathologies, including cancer or diabetes. In cancer, the ERBB/HER family of receptors has been shown to participate in the pathophysiology of breast, gastric, colorectal, lung and head and neck tumors. Activation of HER receptors occurs by receptor-receptor interactions facilitated by ligand binding, overexpression or molecular alterations of the HER receptors. The best example is the known role of HER2 in the tumorigenesis of a proportion of breast tumors. In this review, we will describe the biological bases that govern HER receptor activation, and this will represent the bases for the explanation of how to target HER receptors in cancer. We will discuss the current therapeutic options to target HER receptors, which are based on anti-receptor antibodies or small molecule kinase inhibitors. We will also describe current clinical applications and future developments of agents which target HER receptors. Finally, we will mention mechanism of resistance to anti-HER therapies, and will describe options to overcome such resistances.