Extending Knowledge on Her-Family Receptors for Epidermal Growth Factor and their Ligands to Hematological Malignancies

Abstract

Receptors belonging to the HER (ErbB) family are essential to the development of organs and systems in general. Although their presence is ubiquitous in adult tissues, their over-expression or dysregulation is associated with poor prognosis in many types of tumors. Curiously, the absence of HER and their ligands in mature blood cells has been reported, suggesting a necessary down-regulation during hematopoieis. However, many reports point to their presence in hematological malignancies, suggesting that in the latter, the new drugs currently being developed for other types of cancer will also putatively contribute to the control of cell growth. Formerly known only as transmembrane signal transducers, HER receptors have recently been found in cell nuclei, indicating new signaling routes. Nuclear localization has been described as a prognostic factor in breast cancer, while the extension of this observation to hematological malignancies remains to be investigated.