👷‍♀️ HER2 / ErbB2 Receptor
HER2 is a protein that helps breast cancer cells grow quickly. Breast cancer cells with higher than normal levels of HER2 are called HER2-positive.
Introduction
The ErbB family of proteins contains four receptor tyrosine kinases, structurally related to the epidermal growth factor receptor (EGFR), its first discovered member. In humans, the family includes
- ErbB-1, also named epidermal growth factor receptor (EGFR)
- ErbB-2, also named HER2 in humans and neu in rodents
- ErbB-3, also named HER3
- ErbB-4, also named HER4
Name
HER2 is so named because it has a similar structure to human epidermal growth factor receptor, or HER1. Neu is so named because it was derived from a rodent glioblastoma cell line, a type of neural tumor. ErbB-2 was named for its similarity to ErbB (avian erythroblastosis oncogene B), the oncogene later found to code for EGFR. Molecular cloning of the gene showed that HER2, Neu, and ErbB-2 are all encoded by the same orthologs.
Clinical Significance
Amplification, also known as the over-expression of the ERBB2 gene, occurs in approximately 15-30% of breast cancers. It is strongly associated with increased disease recurrence and a poor prognosis; however, drug agents targeting HER2 in breast cancer have significantly positively altered the otherwise poor-prognosis natural history of HER2-positive breast cancer. Over-expression is also known to occur in ovarian, stomach, adenocarcinoma of the lung and aggressive forms of uterine cancer, such as uterine serous endometrial carcinoma, e.g. HER2 is over-expressed in approximately 7-34% of patients with gastric cancer and in 30% of salivary duct carcinomas.
HER2 proteins have been shown to form clusters in cell membranes that may play a role in tumorigenesis
Function
ErbB protein family signaling is important for development. For example, ErbB-2 and ErbB-4 knockout mice die at midgestation leads to deficient cardiac function associated with a lack of myocardial ventricular trabeculation and display abnormal development of the peripheral nervous system
Reference Links
Keywords / Abbrivations
- prognosis : A prediction of the probable course and outcome of a disease.