Breast cancer, HER2 receptors and Monoclonal antibodies

One thirds of all breast malignancies have amplification of the HER2 gene. HER2 stands for human epidermal receptor type 2. HER2 receptor is a transmembrane tyrosine kinase receptor whose stimulation leads to a number of molecular pathways associated with tumor growth and progression.

Cancers that express HER2 have poorer prognosis.

Trastuzumab also known as Herceptin is a recombinant monoclonal antibody specifically directed against the HER2 receptor and it has been shown to be improve the response rate in breast cancer patients. This antibody is used in combination with chemotherapy including doxorubicin, cyclophosphamide and paclitaxel.
 
Another antibody named Lapatinib (a.k.a. Tykerb) which is a 4-anililoquinazoline kinase that inhibits the tyrosine kinase domains of HER2 receptor is also being studied.

National Comprehensive Cancer Network recommends use of these agents in addition to chemotherapy for patients with HER2-positive breast cancers that are larger than 1 cm and have spread to lymphnodes.

***This topic is hot for the USMLE***