We have trillions of different cells in our body for different parts of our body each of them contains DNA that determines the appearance and behavior of cells.
Sometimes, it is needed to have new cells for replacing old ones or damaging cells. To do this, the new cells make an extra copy of all their DNA and then splits it into two, each with a complete set of DNA instructions.
If DNA has been copied wrongly the cells will die. It may survive but with some mistakes in them. Sometimes these mistakes cause tumors: these mistakes force new cells to behave strangely and splitting into abnormal cells very fast and forming tumors.
Some tumors are cancerous and some of them are not. Cancerous tumors have the ability to grow into neighboring tissue, they should be cured otherwise it may grow and spread to other parts of the body. Tumors that can’t invade the neighboring tissues aren’t cancerous they are benign tumors that don’t need treatment.
Each breast contains 15-20 lobes that are responsible for producing milk and Breast cancer usually begin within them. fatty and fibrous connective tissues in the breast are called stromal tissues. Breast cancer may begin through these issues but it’s not so common. The breast also contains lymph systems and blood vessels that may be a channel for spreading breast cancer to other parts of the body.
Sign and symptom:
Genetic abnormality or the mistake in the genetic material is the reason for breast cancer. It has two reasons: inheritance from mother or father (5-10 %), the result of the aging process (85-90%). The most common symptom of breast cancer is new, painless lumps, but much of the time such lumps aren’t cancer. According to the Mayo Clinic, most of these lumps are benign or noncancerous.
- Common causes of benign breast lumps are:
- Breast infection
- Fibrocystic breast disease(“lumpy breasts”)
- Fibro-adenoma(noncancerous tumor)
- Fat necrosis(damaged tissue)
Some signs of breast cancer are :
- The shape of the nipple will be changed
- Continued breast pain even after your next period
- Continued new lump even after your next period
- Clear, red, brown, or yellow nipple discharge from one breast
- Unexplained redness, swelling, skin irritation, itchiness, or rash on the breast
- Swelling or a lump around the collarbone or under the arm that gets bigger
- Enlargement of one breast
- Exciting dimples on the surface of the breast
- Vaginal pain
- Weight loss without any obvious reason
- Visible veins on the breast
Having one or some of these reasons necessarily is not the reason for having cancer. A new lump or MASS is the most common symptom of Cancer. So it is important to ask a health care professional experienced in diagnosing breast diseases for checking these symptoms.
Classification of breast cancers
There are several grading systems for classifying breast cancers and each of them can affect the prognosis and treatment response.
- Histopathology: classification of breast cancer by its histological
- Grade: classification of breast cancer according to the Grading that is comparing the appearance of the breast cancer cells to the appearance of normal breast tissue.
- Stage: classification of breast cancer according to the staging that is done by the use of the system. This system is based on the size of the tumor (T), whether or not the tumor has spread to the lymph nodes (N) in the armpits, and whether the tumor has metastasized (M) or spread to a more distant part of the body.
- DNA assays. various types of DNA testing like DNA microarrays in which normal cells will be compared with breast cancer cells.
- Receptor status. On the surface of Breast cancer cells surface and also and in their cytoplasm and nucleus, there are some that Chemical messengers such as hormones that bind to them, and because of it, some changes may occur in the cells. Three important receptors that breast cancers cells may or may not have are estrogen receptor (ER), progesterone receptor (PR), and HER2.
ER+ cancer cells have estrogen receptors so they need estrogen for their growth, these kinds of cells can be treated with drugs to block estrogen effects like tamoxifen. This kind of cancer has a better prognosis. Generally, HER2+ breast cancers are more aggressive than HER2- breast cancers, these cells respond to drugs such as the monoclonal antibody trastuzumab. Cells without any of these three receptor types (estrogen receptors, progesterone receptors, or HER2) are called triple-negative.
HER2+ Breast Cancer
HER2 stands for Human Epidermal Growth factor Receptor 2. It is a type of gene that can play a role in the development of breast cancer. ERBB2 (Erb-B2 receptor tyrosine kinase 2) gene is the other name of HER2 gene that in some studies refers to.
Approximately 1 in 5 patients with breast cancer have HER2+ breast cancer. All breast cancers are not the same. HER2+ breast cancer cells have more HER2 receptors than normal breast cells and because of these receptors, the cancer cells grow and divide faster, creating more HER2+ cancer cells. This kind of cancer is considered aggressive because it grows and spreads quickly.
Treatment for HER2+ Breast Cancer
There are medicines specifically for HER2-positive breast cancers, they are:
- Herceptin (chemical name: trastuzumab): blocking the cancer cells’ ability to receive chemical signals that tell the cells to grow.
- Kadcyla (chemical name: T-DM1 or ado-trastuzumab emtansine): the combination of Herceptin and the chemotherapy medicine emtansine, Kadcyla; attaching emtansine to Herceptin and delivering emtansine to cancer cells in a targeted way.
- Nerlynx (chemical name: neratinib): block the ability of cancer cells to receive growth signals.
- Perjeta (chemical name: pertuzumab): blocking the ability of cancer cells to receive growth signals like Herceptin.
- Tykerb (chemical name: lapatinib): blocking the ability of certain proteins that can cause uncontrolled cell growth