For the HER2+ aspect of my cancer, I received weekly Herceptin treatments during my chemotherapy cycles. I continue to receive Herceptin now, every three weeks, until April 2010.
The following is an overview or Herceptin. (source: www.herceptin.com)
What is HER2?
Studies show that approximately 25% of breast cancer patients have tumors that are HER2+. HER2 stands for Human Epidermal growth factor Receptor 2. It is very important to find out your cancer’s HER2 status. This is because HER2+ tumors tend to grow and spread more quickly than tumors that are not HER2+. In addition, the treatment of HER2+ breast cancer is different than the treatment of breast cancer that is not HER2+. Women who are uncertain of their cancer’s HER2 status should talk to their doctor.
HER2+ breast cancer is aggressive, so it is important to find out your cancer’s HER2 status. This can help your doctor choose which treatments may be right for you.
How is HER2 positive breast cancer different?
HER2 stands for Human Epidermal growth factor Receptor 2. Each normal breast cell contains copies of the HER2 gene, which helps normal cells grow. The HER2 gene is found in the DNA of a cell, and this gene contains the information for making the HER2 protein. 4
The HER2 protein, also called the HER2 receptor, is found on the surface of some normal cells in the body. In normal cells, HER2 proteins help send growth signals from outside the cell to the inside of the cell. These signals tell the cell to grow and divide. 4
In HER2+ breast cancer, the cancer cells have an abnormally high number of HER2 genes per cell. When this happens, too much HER2 protein appears on the surface of these cancer cells. This is called HER2 protein overexpression. Too much HER2 protein is thought to cause cancer cells to grow and divide more quickly. This is why HER2+ breast cancer is considered aggressive.
What is Herceptin?
Herceptin (chemical name: trastuzumab) can be an effective treatment both before and after surgery for people with HER2-positive breast cancer. It has also been shown to reduce the risk of breast cancer recurrence after initial surgery.
How does Herceptin Work?
Cancer cells grow in an uncontrolled fashion. Herceptin works on the surface of the cancer cell by blocking the chemical signals that can stimulate this uncontrolled growth.
Genes are like instruction manuals that tell each cell of our body how to grow, what kind of cell to become, and how to behave. Genes do this by ordering the cell to make special proteins that cause a certain activity — like cell growth, rest, or repair.
Some cancer cells have abnormalities in genes that tell the cell how much and how fast to grow. Sometimes the cancer cells have too many copies of these genes with abnormalities. When there are too many copies of these genes, doctors refer to it as “overexpression.” With some forms of gene overexpression, cancer cells will make too many of the proteins that control cell growth and division, causing the cancer to grow and spread.
Some breast cancer cells make (overexpress) too many copies of a particular gene known as HER2. The HER2 gene makes a protein known as a HER2 receptor. HER2 receptors are like ears, or antennae, on the surface of all cells. These HER2 receptors receive signals that stimulate the cell to grow and multiply. But breast cancer cells with too many HER2 receptors can pick up too many growth signals and so start growing and multiplying too much and too fast. Breast cancer cells that overexpress the HER2 gene are said to be HER2-positive.