Different forms of cancer have different presenting symptoms.  All cancers involve the abnormal growth of cells, but the symptoms vary depending upon where the growths are located.  For example, if someone were to have skin cancer, there could be irregularities in shape, edges, color, and size in brownish spots on their skin such as freckles, birthmarks, and moles.  Lung cancer, unfortunately, often has no symptoms until the tumor has become quite large or has spread.  One of the first signs might be a cough that lasts a long time and slowly grows worse.  By then, cancer cells from the lung have often spread to other parts of the body and started other tumors there.  For these reasons, lung cancer is usually very hard to treat.  Leukemia makes one feel tired all the time, causes frequent nosebleeds, bruises, and patients tend to have a chronic head cold, or have one infection after another.

In most forms of cancer a tumor, or lump of abnormal cells, forms in a certain part of ones body. Cancer (tumors) can  either be malignant or benign. Malignant means the tumor has spread throughout the body and affected other organs. Benign tumors do not travel through ones body and stay where they originate. Most skin cancers are local and grow very slowly. However, melanoma is a form of skin cancer which travels throughout the body at a very rapid rate. With lung cancer the tumors destroy the lungs' ability to transmit oxygen to the blood. Leukemia is a cancer of the white cells in the bone marrow. The cancer causes them to divide at an abnormally high rate. This prevents the normal production of other types of blood cells, particularly red ones. The lack of red blood cells keeps the body from getting oxygen.