What is HER2?

The focus of recent research into the cause of cancer has been the cell systems controlling growth. This has shown that mutations affecting growth factor receptors are involved in oncogenesis. The human epidermal growth factor receptor (HER) family is one of the best characterized systems in breast cancer and has important functions in the control of normal growth regulation. HER2 has a central role in the HER family, interacting with the other members of this receptor family to potentiate intracellular signalling. Although our understanding of how HER2 functions and is regulated is limited, studies have linked HER2 gene amplification/receptor overexpression to cancer development. HER2 gene amplification/receptor overexpression is observed in a significant proportion of various tumour types, occurs relatively early during cancer progression and is associated with poor prognosis in women with breast cancer. Knowing the HER2 status of patients with breast cancer will become increasingly important for making management decisions.