EphB4: A promising target for upper aerodigestive malignancies.

The erythropoietin-producing hepatocellular carcinoma (Eph) receptors are the largest family of receptor tyrosine kinases (RTKs) that include two major subclasses, EphA and EphB. They form an important cell communication system with critical and diverse roles in a variety of biological processes during embryonic development. However, dysregulation of the Eph/ephrin interactions is implicated in cancer contributing to tumour growth, metastasis, and angiogenesis. Here, we focus on EphB4 and review recent developments in elucidating its role in upper aerodigestive malignancies to include lung cancer, head and neck cancer, and mesothelioma. In particular, we summarize information regarding EphB4 structure/function and role in disease pathobiology. We also review the data supporting EphB4 as a potential pharmacological and immunotherapy target and finally, progress in the development of new therapeutic strategies including small molecule inhibitors of its activity is discussed. The emerging picture suggests that EphB4 is a valuable and attractive therapeutic target for upper aerodigestive malignancies.