Monday, April 2, 2007

Cancer Case - What is Cancer ? (Part I)

Cancer is a diseases characterized by rapid uncontrolled division of cells (cell proliferation) .This cancerous cells have the ability to spread, either by direct growth into adjacent tissue , or by spreading into distant sites through the bloodstream or lymphatic system ,This is called as metastasis which results in damage of tissues adjacent to the cancerous cells. Cancer can occur to people of all ages, but it’s more probable to affect aged people (that is probability of occurrence increases as age increases). This disease is one of the principal causes of death in developed countries.

Cancer is seen not only in human beings but also in other organisms. This confirms that cancer is caused due to external factors that cause mutation (disturbance) in biological cells but not a hereditary factor. The factors may be external heat ,radiations (radio active dusts), harmful UV rays , certain chemicals , dissolved metallic dusts like lead , food we take (Bowel cancer due to beef consumption ), cigarette, drinks etc. In Current technology, using certain microwave devices causes mutation to the sensitive cells near to it. For example use of cell phone for a longer conversation produces heat that affect brain cells causing brain tumor. Even the physical stress too can cause cancer (Women wearing tight bra have high probability of being affected by breast cancer). The causative agents are termed as carcinogens.

Cell proliferation hi is a common physiological process that occurs in almost all tissues. Normally there will be balance between cell division (creation) and cell death, this ensure the integrity of organs and tissues. Mutations in cell's DNA strands leads to cancer disrupting these orderly processes. The uncontrolled and often rapid proliferation of cells can lead to either a benign tumor or a malignant tumor (cancer). Benign tumors do not spread to other parts of the body or invade other tissues, and they are rarely a threat to life unless they extrinsically compress vital structures. Malignant tumors can invade other organs, spread to distant locations (metastasize) and become life-threatening one.

Severity of cancer depends on the site and character of the malignancy and the rate of metastasis. A cancer with high metastasis rate is considered as malignant .Usually the cancer is identified by examining the cell growth and division rate of tissues by pathologist. This tissue is obtained by biopsy or surgery. Cancer at the benign level can be cured since the cancerous cells didn't enter the blood stream, and severity depending on the specific type, location, and stage. Once diagnosed, cancer is usually treated with a combination of surgery, chemotherapy and radiotherapy. As research develops, treatments are becoming more specific for the type of cancer pathology. Drugs that target specific cancers already exist for several types of cancer. If untreated, cancers may eventually cause illness and death, though this is not always the case. The unregulated growth that characterizes cancer is caused by damage to DNA, resulting in mutations to genes that encode for proteins controlling cell division. Many mutation events may be required to transform a normal cell into a malignant cell. These mutations can be caused by radiation, chemicals or physical agents that cause cancer, which are called carcinogens, or by certain viruses that can insert their DNA into the human genome. Mutations occur spontaneously, and may be passed down from one cell generation to the next as a result of mutations within germ lines. However, some carcinogens also appear to work through non-mutagenic pathways that affect the level of transcription of certain genes without causing genetic mutation. Many forms of cancer are associated with exposure to environmental factors such as tobacco smoke, radiation, alcohol, and certain viruses. Some risk factors can be avoided or reduced.

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