What is HER2 positive cancer?

• The HER2 gene encodes the receptor tyrosine kinase HER2 and is often over-expressed or amplified in breast cancer and gastric cancer.^1,2 Up-regulation of HER2 contributes to tumor progression.¹
• Breast cancers can have up to 25–50 copies of the HER2 gene, and up to 40–100 fold increase in HER2 protein resulting in 2 million receptors expressed at the tumor cell surface.³
• Increased HER2 signaling plays a role in increasing proliferation and survival of the primary tumor and distant lesions which upon completion of full transformation cause metastasis.³
• Approximately 1 in 4 patients with breast cancer has HER2-positive breast cancer.^4,5
• About 1 out of 5 of gastric cancers has too much of a growth-promoting protein called HER2/neu (or just HER2) on the surface of the cancer cells.²

Figure: Normal cell (A) / Overexpressed HER2 (B)

Methods for HER2 testing⁶

• IHC Test - Immunohistochemistry test - Cancer cells are examined under a microscope to see whether there is too much HER2 protein present on the cell surface.
• FISH Test – Fluoroscence insitu hybridization test - The cell nucleus controls cell growth and reproduction. FISH testing measures the number of copies of the HER2 gene in the nucleus.

How is HER2 testing conducted?

• The pathologist will interpret the results and score the patient as HER2-positive, HER2-negative, or equivocal (which means that the tumor is considered neither HER2-positive nor HER2-negative)
• IHC test results are scored as negative (0 or 1+), equivocal (2+), or positive (3+).⁶
• FISH test results are scored as negative, equivocal, or positive.⁶

What is the significance of HER2 positive breast cancer?

Accurate HER2 testing is extremely important. If you are HER2-positive, you can have benefit from a therapy that targets HER2.

Vivitra^TM ( Trastuzumab ) is indicated for the treatment of patients with HER2 overexpressing metastatic breast cancer.⁷

• Vivitra^TM (Trastuzumab) is also indicated in combination with aromatase inhibitor for the treatment of patients with HER2 overexpressing and hormone receptor-positive metastatic breast cancer.⁷
• Vivitra^TM (Trastuzumab) is indicated for the treatment of patients with HER2 overexpressing early breast cancer following surgery, chemotherapy (neo adjuvant or adjuvant) and radiotherapy (if applicable).⁷

Vivitra^TM (Trastuzumab) is also indicated for adjuvant treatment of patients with HER2 overexpressing node positive or node negative breast cancer i) as part of treatment regimen comprising doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel ii) with docetaxel and carboplatin.⁷

What is the significance of HER2 positive gastric cancer?

Vivitra^TM (Trastuzumab) is indicated for the treatment of patients with HER2 overexpressing metastatic gastric or gastroesophageal junction adenocarcinoma in combination with capecitabine or 5- fluorouracil and cisplatin who have not received prior anti-cancer treatment for their metastatic disease.⁷

References

1. Freudenberg JA, Wang Q, Katsumata M, Drebin J, Nagatomo I, Greene MI. The role of HER2 in early breast cancer metastasis and the origins of resistance to HER2-targeted therapies. Exp Mol Pathol. 2009 Aug;87(1):1-11
2. Gravalos C, Jimeno A. HER2 in gastric cancer: a new prognostic factor and a novel therapeutic target. Ann Oncol. 2008 Sep;19(9):1523-9.
3. Gutierrez C, Schiff R. HER2: biology, detection, and clinical implications. Arch Pathol Lab Med. 2011 Jan;135(1):55-62.
4. Pegram M, Slamon D. Biological rationale for HER2/ neu (c-erbB2) as a target for monoclonal antibody therapy. Semin Oncol. 2000;27(suppl 9):13-19.
5. HER2 status. Breastcancer.org. http://www.breastcancer.org/symptoms/diagnosis/her2. Updated March 10, 2015. Accessed on november 2015.
6. ASCO 2013 Wolff AC, Hammond ME, Hicks DG, Dowsett M, McShane LM, Allison KH, Allred DC, Bartlett JM, Bilous M, Fitzgibbons P, Hanna W, Jenkins RB, Mangu PB, Paik S, Perez EA, Press MF, Spears PA, Vance GH, Viale G, Hayes DF; American Society of Clinical Oncology; College of American Pathologists. Recommendations for human epidermal growth factor receptor 2 testing in breast cancer: American Society of Clinical Oncology/College of American Pathologists clinical practice guideline update. J Clin Oncol. 2013 Nov 1;31(31):3997-4013.
7. Vivitra^TM (Trastuzumab) Prescribing Information