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Hormone are essential as our body chemical messengers. They travel to their target cells in bloodstream/ intracellular fluid. These hormone are responsible for growth and development, sexual function, reproduction, metabolism and mood.
Endocrine glands are parts of endocrine system. They are special groups of cells, that are responsible to produce hormones. The major endocrine glands are the hypothalamus, pituitary gland, parathyroid, thyroid gland, adrenal gland, pancreas, ovary and testis. In addition, men produce their sexual hormones in their testes and women produce them in their ovaries.
Hormones are great in term of their effects. It takes only a tiny amount to cause big impacts in cells or even our whole body. That is the reason for too much or too little of a certain hormone can be a serious matter.
1.2 CANCER CELLS
Cancer can be described as any of a group of diseases which are characterized by the uncontrolled growth of cells that can cause damages to tissues and organs in the body, and can lead to death. Cancer cells develop when normal cells become damaged and then they multiply. It is common for a cell to form abnormally or being damaged, but in most cases the cell will simply destructs itself by a process called apoptosis. This is due to the fact that cancer cells show normal properties to the immune system in our body. Hence, it is recognized as normal cells and will not be attacked.
Most cancer cells multiply and stay put at the same spot, at least at first, then forming a tumor. However, it should be notified that not all tumors are cancerous. There are two types of tumor, which are benign and malignant.
Benign tumors are growth of cells that can share certain characteristics with cancerous tumors, but are self-limiting and non-destructive. They mostly do not infecting neighbor cells and will not redevelop after they are removed.
Malignant or cancerous tumors however, formed as a result of a mutation or other alteration to the genetic material of a normal cell. This occurrence itself happens often in the body, but it almost always self-destructive which will be stopping the mutation from spreading out. This fact shows how essential apoptosis process is in order to maintaining the survival of living organisms. The mutated cell if not destroyed will allow it to duplicate, and then these two cells will divide, forming more.
3. DEVELOPMENT OF CANCER CELLS
Cancer begins when a cell divided from the normal restraints on cell division and begins to follow its own for proliferation (Figure 3). All of the cells produced by division of this first, ancestral cell and its progeny also display abnormal proliferation. A tumor also known as a mass of cells, formed of these abnormal cells may localized (a condition called in situ cancer), or it may begin to spread to nearby tissues (a condition called invasive cancer). An invasive tumor is known as malignant, and cells diffuse into the blood or lymph from a malignant tumor are likely to establish new tumors (metastases) throughout the body. Tumors endangered individual's life when their growth destroyed the tissues and organs needed for survival.
Figure 3 - The stages of tumor development. A malignant tumor develops by stages, as shown in this diagram. This tumor develops as a result of four mutation stages, but the number of the stages involved in other types of tumors can vary. A) The tumor begins to develop when a cell mutated that makes the cell more likely to divide abnormally. B) The altered cell and its descendants grow and divide actively, a condition called hyperplasia. At some point, one of these cells undergoes another mutation that further increases its tendency to multiply. C) This cell's descendants will divide excessively and looked abnormal, a condition called dysplasia. Sooner or later, one of the cells will experience yet another mutation. D) This cell and its descendants are very abnormal in their development and appearance. If the tumor that has formed from these cells remains at its original site, it is called in situ cancer e) If some cells experience additional mutations that allow the tumor to spread into neighboring tissues and shed their cells into the bloodstream or lymph, the tumor known as malignant. The diffused cells may establish new tumors (metastases) at other locations throughout the body.
2. Hormone Therapy
Hormone replacement therapy (HRT) described as the use of a set of hormones (namely estrogen and progesterone) in the treatment of menopause. Menopause is a common disease which causes a woman to produce less estrogen. She can experience a number of symptoms such as mood swings, hot flashes, a decreased sex drive and vaginal dryness. The theory behind hormone replacement therapy is that, by reintroducing the hormone involved (estrogen) to a menopausal woman's body, these uncomfortable symptoms can be reduced.
However, there are reports revealed that increased levels of estrogen in the blood can be linked to the development of breast cancer. Thus, HTR is becoming more controversial towards both the researchers and consumers. Basically, those who can respond well to the HTR are women who have both estrogen positive and progesterone positive receptors in their breast cells.
Typically, estrogen is the hormone that is responsible for triggering and regulating menstruation cycle of women, as well as the development of female sex organs, such as the breasts. Researchers have found that most reported breast cancer's cases show the association of increased levels of estrogen in the blood with the promotion of the abnormal cells in the breast. Doctors have referred to individual that suffer from these breast cancer as "estrogen receptor positive" (ER). Some of postmenopausal patients, fail or disable to respond well to anti-estrogen treatments of hormone receptor positive breast cancer. However, we should notified that not all cases of breast cancer are simply due to the presence of ER positive cells in a woman's breasts.
Nowadays, there are laboratory tests referred as tissue staining which can determine if a cancer is sensitive to hormones. Any tissue staining for estrogen or progesterone receptors (above 0%) proves that hormonal therapy may be effective for the patients. However, women whose cancers do not stain for hormone receptors at all (0%) do not appear to benefit from this method, neither to prevent recurrence, nor to prevent second cancers.
4. HORMONAL THERAPY FOR BREAST CANCER
In the treatment of early stage of cancers, hormonal therapy is commonly used to prevent cancer from invading to neighbor cells or tissues or spreading towards other areas. Basically, the aim is to lower the risk of a second, independent breast cancer. Woman who have cured from a breast cancer have a higher risk to suffer from second unrelated cancers than women who have never had breast cancer.
This method may be effective based on its strategies. The aims are achieved by blocking the function of hormones, reducing the hormone production in the ovaries, which is named as ovarian ablation and also by preventing the production of hormones outside of the ovary by other tissues. Therefore, researchers have came up with a few drugs invented specially for this purpose such as tamoxifen, fulvestrant and goserelin.
Tamoxifen (Nolvodex) has been used for both treatment and prevention of breast cancer. Tamoxifen are known to have both estrogen-like (agonist) and estrogen-blocking (antagonist) effects for women.
Tamoxifen has been approved by the FDA to treat women who suffer from breast cancer for more than two decades and has been in clinically tested for about three decades. Tamoxifen has been the basis treatment for women with estrogen-sensitive breast cancer. More research is being conducted to determine its long-term effectiveness.
A newer drug that works in a similar way to tamoxifen is called by fulvestrant. Fulvestrant functions just like tamoxifen,by attaching to the estrogen receptor. However, unlike tamoxifen, it may destroy the receptors, thereby causing the blockage of all estrogen activity. Hence, the application is less favorable.
Chemical Ovarian Ablation
The drug used for chemical ovarian ablation is known as goserelin. Goserelin functions by reducing the production of luteinizing hormone (LH) from the pituitary gland. This will then leads to a reduction of estrogen secretion. Thus, it results in shrinking of the tumor size, or alternatively slowing down the growth of the cancer.
This treatment is suitable for a premenopausal women who suffer from an early stage receptor-positive breast cancer. However, it is not effective for women who have receptor-negative breast cancer.
Goserelin can be used alone or with other side treatments. Studies have shown that for women below age 50 with early stage of breast cancer, ovarian ablation without chemotherapy treatment improve long-term, recurrence-free survival and overall survival by approximately 30%. Recent studies have suggested that ovarian ablation with the treatment of tamoxifen may be as effective as chemotherapy in certain cases. Further study is prompted to determine if ovarian ablation is more successful when joined with other treatments or when it is applied alone.
All in all, hormone can be beneficial in treatment of cancer and may also 'feed' cancer cells to grow. In recent years, studies about the hormone and its function has improved medical knowledge in the treatment of diseases namely cancer. Since breast cancer is one of the most deadly diseases for women, it is important for us to encourage further studies about this disease regardless based on their development or treatment. This awareness will lead to healthier community since nowadays we encounter many types of environmental pollutions which are the main factors contributing this fatal disease. Hopefully, hormone can be applied as alternative treatment rather than the usage of drugs which may exerts side effects in short or long terms.