Progress essaySeonho lee( Grant )Understanding lung cancerThe average of life expectancy in the U.S is 77.8 years. However, there is a potential to die when even younger. Lung cancer, so-called non small cancer, is one type of cruel diseases which can cause people to die. According to the American Cancer Society, about 154,900 people died of this disease in 2002: 89,200 men and 65,700 women. Although the growth of the cancer and invasion of lung tissues and surroundings may interfere with breathing, leading to symptoms such as cough, shortness of breath, and chest pain, up to 25% of the people who get lung cancer do not have any symptoms when the cancer is found. In order to understand this disease, information about how it is caused, how it spreads, and how to treat cancer is beneficial.Researchers have discovered several causes of lung cancer such as personal history, lung disease, and pollution, but the most common are related to the use of tobacco. First of all, Smoking cigarettes causes lung cancer. Harmful substances in tobacco, called carcinogens, damage the cells in the lungs. As time goes by, the
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