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CELL DIVISION GOING WRONG: Cancer
2.7 When cells grow and divide out of control, they cause a group of diseases called cancer. The result is a change in the DNA that controls the cell cycle. This change prevents the cell from staying in interphase for the normal period of time. When the normal checkpoints fail, the cell and its daughter cells will divide uncontrollably. cancer
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broad group of diseases associated with uncontrolled, unregulated growth of cells
cancer begins when the signaling pathways of the cell cycle clock controls fail cells communicate information about the body’s needs from one cell to another (i.e a callus forms as accelerated cell division not only replaces damaged cells, but also increases the cell numbers of the epidermis to shield the nerve and blood vessels in the inner layers)
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CELL DIVISION GOING WRONG: Cancer
2.7 TUMOURS Uncontrolled growth may create a rapidly growing mass of cells that form a lump, or tumour. Tumours may be benign or malignant. Cells in a malignant tumour are considered cancerous. Cancer cells may break away from the original tumour and move to a different part of the body. If they settle and grow in this new location, a new tumour will form. This process of breaking away and creating secondary tumours is called metastasis.
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cancer cells can divide in isolation at a very rapid rate, without directions from adjacent cells, (although some cancers grow more slowly as their reproductive rate is regulated somewhat by adjacent cell signals) isolation of cancer cells from each other and normal cells (they don’t stick) allows them to become dislodged from a tumour and metastasize (move to another area) making it difficult to locate and control a large health risk factor arises because cancer cells do not specialize into one of the 100 different types of cells, so they replace normal cells that carry out specific functions (i.e. leukemia replaces normal WBC, reducing ability to fight pathogens)
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CELL DIVISION GOING WRONG: Cancer
2.7 MUTATIONS When cells divide, their DNA is almost always duplicated error-free. The genetic information in their daughter cells is identical to the parent cell. Sometimes random changes occur in the cell’s DNA. These changes are called mutations. Changes may result in the death of the cell or allow it to survive and continue to grow and divide. If the cell cycle is abnormal, the cells may be cancerous. mutations carcinogens
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CELL DIVISION GOING WRONG: Cancer
2.7 CARCINOGENS Some mutations are caused by carcinogens. Carcinogens are environmental factors that cause cancer. Examples include tobacco smoke, radiation, some viruses, certain chemicals, and many organic solvents. Lung cancer is the most common type of cancer in Canadians over 40 years of age. Health Canada reports that 9 out of 10 lung cancer cases are caused by smoking. The figure at the right identifies other parts of the body that are affected by the carcinogens in tobacco smoke. Some cancers are at least partly hereditary. These include some breast cancers and colon cancers. mutations carcinogens
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CELL DIVISION GOING WRONG: Cancer
2.7 CANCER SCREENING Factors affecting a person’s risk of getting cancer include personal and family medical history exposure to carcinogens in the environment lifestyle choices, such as eating more “super foods” Cancer screening means checking for cancer even when no symptoms are present. Screening can be performed at home, as part of a routine self-examination by a doctor, such as a Pap test or blood test as genetic testing, when there is a family history of cancer While screening does not prevent cancer, it does increase the likelihood of early detection and successful treatment. pap test Super foods such as these help your body protect itself from cancers
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CELL DIVISION GOING WRONG: Cancer
2.7 CANCER DIAGNOSIS AND TREATMENT The earlier a cancer is diagnosed, the better the chances of successful treatment. Some diagnostic imaging techniques include endoscopy, X-ray, ultrasound, CT scanning, and MRI. Once an abnormality has been identified, a sample of the cells is removed and examined under a microscope. This is called a biopsy. This is the only way to positively confirm a diagnosis of cancer. The purpose of cancer treatment is to slow down the growth of tumours or destroy as many cancer cells as possible. Currently, there are three methods of conventional treatment: surgery chemotherapy radiation therapy One new technique to fight cancer is biophotonics, which uses beams of light to detect and treat the cancer cells. Vocabulary Pap test
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