“Cancer is a class of diseases characterized by uncontrolled cell growth. There are more than 100 different types of cancer, and each is classified according to the type of cell initially affected” (What is Cancer? What Causes Cancer?,1). Most cancers harm the body when cells begin to divide and form clumps of tissue called tumors. However, leukemia affects cells in the bloodstream. Although some tumors can grow and affect many different systems in the body, some are not dangerous and are called benign tumors. There are many types of cancer, some more dangerous than others. The most commonly diagnosed cancers include breast cancer, ovarian cancer, kidney cancer, colon and rectal cancer, and lung cancer. Breast cancer is characterized by a malignant or cancerous tumor that develops in the cells of the breast. In most cases of breast cancer, the cancer begins in the cells of the milk-producing ducts. If these cancer cells travel to other, uninfected breast tissue, they can travel to lymph nodes under the arms. Once inside the lymph nodes, the cancer can spread to other parts of the body. Breast cancer stages are determined by the extent to which the cancer cells have spread beyond the original tumor. Many women diagnosed with breast cancer report that the first sign is a lump of tissue felt on the breast. Despite this, most women brush off these bumps and do not get tested in time. Other symptoms of this type of cancer include swelling of all or part of the breast, skin irritation, breast pain, or a lump under the arm. It's possible, however, that some of these symptoms signal something less serious, like a cyst. “About 1 in 8 American women (just under 12%) will develop invasive breast cancer in the country...... middle of article......mptoms/understand_bc/statisticsNo Author. (2013). Statistics. Accessed February 4, 2014 from http://www.ovariancancer.org/about-ovarian-cancer/statistics/No Author. (2013). Lung cancer. Accessed February 4, 2014, from http://www.cancer.org/cancer/lungcancer-non-smallcell/detailedguide/non-small-cell-lung-cancer-key-statisticsNo Author. (2013). What is kidney cancer? Retrieved February 4, 2014 from http://www.cancer.org/cancer/kidneycancer/detailedguide/kidney-cancer-adult-what-is-kidney-cancerNo Author. (2013). What is colorectal cancer? Accessed February 4, 2014, from http://www.cancer.org/cancer/colonandrectumcancer/detailedguide/colorectal-cancer-what-is-colorectal-cancerNo Author. (2013). Types of treatment. Accessed February 4, 2014 from http://www.cancer.org/treatment/treatmentsandsideeffects/treatmenttypes/treatment-types-landing