Her 2 Receptor in Breast Cancer Patients
What is importance of Herceptin therapy in breast cancer patients?
Often when patient is diagnosed with breast cancer then oncologist may advice hormonal tests like ER (Estrogen receptor), PR (Progesterone receptor) and HER2 receptor study. Her 2 means Human Epidermal Growth Factor Receptor. These tests are done on sample of biopsy tissue. There is no need to do blood collection for these tests.
What is Human Epidermal Growth Factor Receptor (HER 2)?
Cancer tumor is made up of large number of cancer cells. Each cell is made up of cell membrane, cytoplasm and nucleus along with genetic material along with it. Cancer cells have unique ability of accelerated growth and replication. This replication is governed by multiple receptors present on cancer cell wall. HER 2 is one of it. HER 2 receptor is present on 15 to 30 % of all patients diagnosed with breast cancer. It is also seen in some other cancers like gastric, lung, ovary, endometrium and lung cancers. When a ligand binds the HER2 receptor there is a cascade of events in the cell leading to proliferation of cell. HER2 gene amplification is associated with shorter disease-free and overall survival in breast cancer.
How to test for HER 2 receptor?
Test for HER2 is done on the tissue sample blocks of biopsy specimen. It is done by two methods Immunohistochemistry (IHC) or FISH (Florescent in situ hybridization).
What is the benefit of HER 2 testing in breast cancer?
There are certain drugs which target these receptors. The most commonly used drug is Herceptin or Transtuzumab. Inclusion of trastuzumab in the HER2 +VE breast cancer patients produces roughly a 50% improvement in disease-free survival and 33% improvement in overall survival. The
duration of Herceptin therapy is one year after surgery for breast cancer and till disease progression for metastatic breast cancer.
What are the indications of Herceptin treatment?
1. Treatment of HER2 overexpressing breast cancer
2. Treatment of HER2 overexpressing gastric and gastroesophageal junction adenocarcinoma cancers
How transtuzumab / Herceptin is given?
Herceptin is given by intravenous rout in diluted form. Premedication is needed before injection. It is either given weekly or 3 weekly depending on the stage of chemotherapy.
What are the side effects of Herceptin?
Most important side effects of Herceptin are heart failure, allergic reaction during infusion and lung toxicity. Heart related toxicity occurs in approximately 3 % patients. Allergic reactions are rare but can occur.