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Cancer

Cancer
Today there are one in three people worldwide who are affected by cancer, and almost 60% of these people will almost certainly die. 7000 New Zealanders die every year from this disease. It is the second largest killer next to heart disease. Cancer does not just affect certain groups of people, it can affect anybody and it is not just one disease, it refers to more than a hundred diseases. Cancer is caused by carcinogens. At present, hundreds of chemicals are known to induce cancer. Normally, the body’s cells divide in an orderly way, allowing the body to grow and to heal after injury. Damage or mutations that occur to the proto-oncogenes (POG) and tumour suppresser Genes (TSG) in the genetic material (DNA and RNA) by these carcinogens bring about Cancer, which causes cells to have less control of cell division and differentiation. POGs lead to changed cells or transformed cells and cause excessive cell division. Further mutations cause the cells to become immortal. These cells continue to divide and form a ball of cells. These cells require a lot of energy and fluids flowing to maintain the high rate of the cell division. When these balls become too large for fluids to flow through, the middle of the ball dies. TSG’s act as anti-proto-oncogenes, they regulate the rate of cell division. POG’s and TSG’s constantly compete to overpower each other. These TSG’s can be mutated and this brings about a change in the control mechanism of cell division. Cells are stimulated to divide through a growth factor. Growth factor molecules bind to cell membranes of cells and send a chemical message to a receptor in the cell membrane. The receptor sends a message through the cytoplasm to the nucleus to stimulate cell division. Sometimes when these growth factors are absent the receptor in the cell membrane is mutated to send out the message to the nucleus. Cells are also stimulated to divide through the two proteins, cyclins and cyclin-dependent kinases. When these two join together, this stimulates cell division. These proteins act on the growth inhibitor proteins P53 and PRP, which are growth inhibitor proteins. Tumours may be malignant, spreading or benign, non-spreading. Malignant tumours are aggressive, invasive, and mobile. They invade healthy tissue and continue to divide. The original cancer is called the primary tumour. If the tumour is malignant, the disease may develop in other parts of the body where secondary tumours may form. This is known as metastasis. Cancer causes illness through local growth, spread to distant organs, and overall effects of the disease on the individual. Treatments of cancer vary. Tumours may be surgically removed if they have not metastasised. Other methods are usually used if the tumour has metastasised. For chemotherapy drugs are used to kill cancerous cells as they divide. Radiotherapy is another standard way of treating cancer, ionising radiation aimed at the tumour will prevent the cells from dividing further. So what makes cancer more special than other diseases? The answer is that there is no cure and scientists are not optimistic of finding one in the near future. Today people are far more knowledgeable about cancer and how it may be avoided than 10 years ago. It has now been found that as many as 80% of all cancers may be avoidable. The most common types of cancer in New Zealand are female breast (14%), male prostate (14%), trachea, bronchus, and lung (12%) and colon (11%) Given that such a large proportion of cancers may be avoidable, why isn’t there a reduction in cancer incidence? This may be because our educational programs are not appropriate and perhaps even due to people’s ignorance. Female breast cancer and male prostate cancer can almost always be cured if detected and treated in time. For the early detection of female breast cancer appropriate programs such as monthly mammogram and breast self-tests have been introduced. But I believe that male prostate cancer has not been addressed enough (more?). 80% of lung cancers have been found to be caused by smoking. Today billions of dollars are spent throughout the world on cancer especially in developed countries of the western world where a lot of money is freely available. Most of this research is carried out by private organisations and therefore ethnic minorities appeal to be included in their research. Dietary factors underlie as many as 35% of all cancers. Of this 35%, almost 80% of the patients are colon cancer patients. The government has taken on a major preventative scheme, introducing the 5+a day dietary standards to improve the intake of more fruits and vegetables into people’s daily diets. This aims at reducing bowel cancer in New Zealand, which will no doubt save lives. For these reasons, cancer is a contemporary issue. Biological, ethical and social issues surround it. It also seems that a lot has been done to prevent it but there is so much further to go, and this would ultimately reduce the number of lives that the cancer claims.
References
http://cancernet.nci.nih.gov/
http://www.fhcrc.org/
http://www.cancerresearch.org/