HER-2/ neu Breast Cancer-the positive side

her 2 neu is a protooncogene that encodes the growth factor receptor her-2 (membrane receptor). Membrane receptors are protein molecules which are present on the outside of cell membranes and help in the communication of cell to the external environment. HER- 2 /neu belongs to the epidermal growth factor family. Growth factors are those when activated will result in a cascade of activities of various pathways resulting in cell division and growth. So if these genes are found excessively on the cell surface of tumor cells, its activation will result in tumor growth and progression.

HER-2 /neu are found excessively in 25-30% of invasive breast cancers and it is considered to be a major prognostic factor for breast cancers.

Over expression of HER2/ neu is associated with increased aggressiveness of the disease, increased chance of recurrence, bad prognosis and mortality. However, there are drugs to treat her2 positive breast cancers and with treatment the prognosis of her2 breast cancer is better.

American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) recommend Immunohistochemistry followed by fluorescence in situ hybridization (FISH) to diagnose HER-2/ neu breast cancers.

Immunohistochemistry (IHC) is the application of immunologic techniques in identifying abnormalities in cell structure. It uses specific antibodies to localize particular antigen in the cells, which can be visualized by a marker.

FISH (Fluorescence in situ hybridisation) uses genetic techniques to find out specific DNA sequences or patterns of genes in cells.

Test results will show that a particular patient is HER-2/neu positive or negative. If a patient is HER-2/neu positive it means that that there are over expressions of this particular gene on the breast cancer cell surface and the tumor could be aggressive i.e., it can multiply and grow at a faster rate.

In addition to surgery, chemotherapy and radiotherapy HER-2/neu breast cancers are treated with drugs like trastuzumab and lapatinib currently.

Trastuzumab (Herceptin) is a recombinant monoclonal antibody against HER-2 neu and is found to be effective against such breast cancers in many clinical trials. It is seen to improve the survival (number of years the person is expected to live after diagnosis) of HER-2 neu positive breast cancer patients. Trastuzumab does not have much side effects other than cardiotoxicity.

Lapatinib interrupts epidermal growth factor receptors thereby inhibiting tumor cell multiplication and tumor progression. It doesn’t have many side effects other than gastrointestinal disturbances and fatigue.

Breast cancer treatment requires utmost attention of the treating physician. More and more researches are going on in this area of her 2 neu to improve patients’ survival and to reduce the side effects related to the treatment.