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CANCER And Cell Division Glencoe Chapter 2
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What is Cancer? The division of normal cells is controlled. New cells are only formed for 1) growth 2) to replace dead ones. Cells that are old or not functioning properly normally self-destruct and are replaced by new cells. However, cancerous cells do not self destruct and continue to divide rapidly producing millions of new cancerous cells. Cancer is a disease caused by an uncontrolled division of abnormal cells in a part of the body. Cancerous cells divide repeatedly out of control which form a tumor. Cancerous cells grow and reproduce, even though they are not needed, they crowd out other normal cells and function abnormally. They can also destroy the correct functioning of major organs. A cancerous cell arises from the mutation of a normal gene and duplicates itself during cell division. (Scroll Down) http://www.medicalnewstoday.com/info/cancer-oncology/ http://www.medicalnewstoday.com/info/cancer-oncology/
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4 Stages of Cancer 1) Minor multiplying of cells in one area - “cancer in situ” 2) Growth of cells and recruitment of blood vessels etc. to support growth - “tumor” 3) Invasion/destruction of neighboring tissue -“malignant tumor” 4) Spread of cells to new organs - “metastasize” 1. 2.
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Cancer Statistics Cancer is one of the most common diseases in the developed world: Average 1 in 4 deaths are due to cancer There are over 100 different forms of cancer 1 in 17 deaths are due to lung cancer Lung cancer is the most common cancer in men Breast cancer is the most common cancer in women
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Most Common Cancers in Ages 15 to 40 1.Breast CancerBreast Cancer 2.ThyroidThyroid 3.Melanoma (Skin Cancer)Melanoma (Skin Cancer) 4.LymphomaLymphoma 5.Reproduction Cell Tumors (Testicular, Ovarian)TesticularOvarian 6.CervicalCervical 7.ColorectalColorectal 8.Soft Tissue SarcomaSoft Tissue Sarcoma 9.Central Nervous System (Brain, Spinal Cord)Central Nervous System (Brain, Spinal Cord) 10.LeukemiaLeukemia
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Cancer Cell vs. Normal Cell
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2 Types of Cancerous Tumors Benign tumours do not spread from their site of origin, but can crowd out (squash) surrounding cells ex. brain tumour, warts. Usually not lethal/deadly. Malignant tumours can spread from the original site and cause secondary tumours in organs and other tissues (usually is very dangerous-can become lethal/deadly). When the malignant tumors interfere with neighbouring cells and enters blood stream and spreads throughout the body (the gut, glands, lungs etc.) This is called metastasize and is often the last stage and not curable.
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Causes of Cancer Tobacco Smoke Diet Radiation Work Related Chemicals Medicines Microbes and Bacteria Pollution Genetics (family related)
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Tobacco smoke Smoking causes 30% of fatal cancers: lung, upper respiratory tract, esophagus, bladder, pancreas; probably stomach, liver, kidney; implicated in chronic myelocytic leukemia; maybe colon, rectumlung Malignancy depends on frequency of smoking, tar content, duration of habit Passive inhalation of second-hand smoke causes as many deaths as air pollution Understanding Lung Cancer http://www.medicalnewstoday.com/sections/lung_ cancer/videos.phphttp://www.medicalnewstoday.com/sections/lung_ cancer/videos.php
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Normal Lung vs. Cancerous Lung
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Skin Cancers Irregular Moles Irregular skin marks can be cancerous
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Diet: ~ 20-30% of fatal cancers Animal (saturated fat) in general and red meat in particular: colon and rectum; implicated in prostate cancerprostate cancer Salt: high intake may lead to stomach cancer; in very young children in Southeast Asia leads to cancer of the nasopharynx Hot drinks increase risk of esophageal cancer Eating too few vegetables and fruits is associated with higher cancer rates, perhaps by the absence of antioxidants to neutralize free radicals Some natural chemicals may block cell proliferating signals from steroids, e.g. estrogens Overeating is linked to certain cancers: breast and prostate Obesity is a cause of cancer of the endometrium and contributes to postmenopausal breast cancer; increases risk for cancers of the colon, kidney, and gallbladder Alcohol in large quantity, especially with smoking, increases risk of cancer of upper respiratory and digestive tracts How to eat to prevent cancer - Scroll way down http://www.medicalnewstoday.com/info/cancer-oncology/ http://www.medicalnewstoday.com/info/cancer-oncology/
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Radiation: ~ 2% of fatal cancers High frequency UV-B rays damage DNA; cause 90% of skin cancers Radon - radioactive gas is emitted from the earth in some locations Low frequency electric and magnetic fields: perhaps a small risk for childhood leukemia Radio-frequencies - no empirical evidence for increased risk Nuclear radiation - a potential risk for those few exposed CANCER 101 Video http://www.medicalnewstoday.com/sections/lung_ cancer/videos.phphttp://www.medicalnewstoday.com/sections/lung_ cancer/videos.php
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Work, medications, microbes: ~ 5% of fatal cancers Work: asbestos, benzene, formaldehyde, diesel exhaust Radiation and chemotherapy; clinical usefulness outweighs risks of cancer Some immunosuppressive drugs can cause lymphoma Estrogens increase risk of endometrial and breast cancer Steroids to treat aplastic anemia associated with rare cases of liver cancer Microbes Viruses: human papillomavirus, hepatitis, Epstein-Barr, and HIV Bacteria: Helicobacter pylori by causing stomach ulcers
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Pollution: ~ 2% of fatal cancers Urban air pollution seems to increase the risk for smokers but not non- smokers Long-term exposure to high levels of air pollution increases risk 50%
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Reproductive and gynecological factors: ~ 4% of fatal cancers Early age of starting menstration, late age at first pregnancy, and late age at menopause tend to increase the risk for breast cancer Number of offspring is inversely correlated with cancer of the endometrium, ovary, and breast (less children-less cancer)
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How is cancer classified? 1) Carcinomas are characterized by cells that cover internal and external parts of the body such as lung, breast, and colon cancer. 2) Sarcomas are characterized by cells that are located in bone, cartilage, fat, connective tissue, muscle, and other supportive tissues. 3) Lymphomas are cancers that begin in the lymph nodes and immune system tissues. 4) Leukemias are cancers that begin in the bone marrow and often accumulate in the bloodstream. 5) Adenomas are cancers that arise in the thyroid, the pituitary gland, the adrenal gland, and other glandular tissues.
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Treating Cancer - Oncology “Watchful waiting” - appropriate for many cancer in situs (begnign) ex: prostrate cancer. Many never become serious. Surgery - surgically removing the cancer from the body, can cure isolated tumors. Chemotherapy - required when cancer metastasizes or is inoperable (brain). Uses chemicals that interfere with the cell division process - damaging proteins or DNA - so that cancer cells will commit suicide- also kills healthy cells Radiation - can be used before or after metastasis, focusing high-energy rays on the cancer cells. This causes damage to the molecules that make up the cancer cells and leads them to commit suicide. Vaccines - experimental therapy to get immune system to fight cancer. Standard treatment - surgery followed by chemo.
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Socioeconomic differences Poverty is associated with a risky lifestyle: higher rates of smoking, alcohol consumption, poor nutrition, and exposure to certain infectious agents More affluent seem to be prone to cancers of the breast and prostate Racial differences can be traced to lifestyle: diet and environmental exposure Genetic variability is higher within than between races
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OTHER ??? Plastic Bottles??? Do they cause cancer? http://www.videonewslive.com/view/19646 1/some_plastic_bottles_can_cause_cancerhttp://www.videonewslive.com/view/19646 1/some_plastic_bottles_can_cause_cancer
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