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A gene on chromosome 17q11.2-q12 that encodes a member of the epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases. ERBB2 has no ligand-binding domain and thus cannot bind growth factors; it does, however, bind to other ligand-bound EGF receptor family members, forming a heterodimer, stabilising ligand binding and enhancing kinase-mediated activation of downstream signalling pathways (e.g., those involving mitogen-activated protein kinase and phosphatidylinositol-3 kinase).

Molecular pathology
ERBB2 amplification and overexpression commonly occurs in breast and ovarian cancers.


Human epidermal growth factor receptor 2, a receptor that plays an essential role in cell proliferation and differentiation. It is a member of a family of transmembrane tyrosine kinases. The 20 to 25 percent of breast cancers that over-express HER2 have a high rate of recurrence in the first two or three years after surgery. The HER2 gene is on the short arm of chromosome 17. Over-expression of this gene increases the malignancy of affected cancer cells, enhancing growth and proliferation and increasing their metastatic tendency. The monoclonal antibody drug trastuzumab (Herceptin) which blocks this receptor is effective in reducing the dangers of HER2-expressing breast cancers.
References in periodicals archive ?
It is a member of four member family of closely related growth factor receptors, including EGFR or HER1, HER2, HER3, HER4.
With the establishment of HER2 testing as a standard of care for patients with advanced GEA, it is important to note that the treating clinician should not offer HER2-targeted therapy until HER2 positivity is confirmed.
Cases of HER2 FISH testing, performed between April 2015, when the alternate RAI1 probe was available in our laboratory, and October 2015, were identified.
It is our belief that if we can discover therapies which block the activity of WASH, we can develop more effective treatments, which prevent the growth of HER2 breast tumors and their spread.
Another innovation from Roche is HER2 franchise or T-DM1 for women with previously treated HER2-positive advanced breast cancer (second line setting).
When they treated mice modeling HER2-positive breast cancer with a PTP1B inhibitor called MSI-1436 (also called trodusquemine), Tonks and colleagues inhibited signaling by HER2 proteins.
Very high levels of HER2 are found on the surface of cancer cells in women who have HER2-positive breast cancer.
To achieve a higher throughput capability and a more accurate molecular diagnosis, laboratories have been evaluating HER2 copy number quantification with real-time or quantitative PCR with external standards (6) or internal competitor standards (7).
With a relatively low toxicity profile and much available information on its drug6drug interactions and on pharmacokinetics, nelfinavir is ready for clinical testing in HER2 breast cancer patients," the authors wrote.
The test makes it possible "to see and count copies of chromosome 17 and HER2 genes on the same slide, similar to HER2 amplification measurements that have traditionally only been available using fluorescence microscopes," the statement said.
The benefits of trastuzumab in metastatic breast and gastric cancer accrue exclusively to patients with the highest level of HER2 expression (HER2 3+ by immunohistochemistry) or those who have gene-amplified tumors.
For a long time, we have been concentrating on the protein HER2 but now we have this gene that could be responsible for the spread of the cancer.