Cancer is a disease wherein cells abnormally divide without control. These cells are able to invade other tissues and spread to other area of the body through the lymph and blood systems.
Normal body cells develop and divide, and know when to stop growing. Eventually, they also die. But cancer cells continue to develop and divide, and they don't die when they are supposed to.
Cancer cells normally clump together to form tumors. A developing tumor becomes a piece of cancer cells that can destroy nearby normal cells and harm the body's healthy tissues. At times cancer cells separate from the original tumor, move to other parts of the body, where they keep increasing and later can form new tumors. The spread of a tumor to a new area in the body is called metastasis.
There are more than a hundred different kinds of cancer. Usually it is named after the organ where it started. For instance, cancer that begins at the colon is called a colon cancer. Cancer types can be classified into five (5) broader categories.
Carcinoma – is a type that start in the skin or tissues that cover internal organs. It can rise in the colon, breast, lung, liver, prostate, and stomach.
Sarcoma – is a term used to describe a cancer that begins from supportive or connective tissue cells such as bones, cartilage, muscle, fat, and blood vessel.
Leukemia – is a type that begins in blood-forming tissue (eg bone marrow) and causes huge amount of abnormal blood cells to be formed and enter the blood.
Myeloma and Lymphoma – is a type that originates in the cells of immune system.
Central Nervous System Cancers – cancers that start in the tissues of the spinal cord and the brain.
Doctors are not certain why some people get cancer and others don't. What they do know is that cancer is not contagious and that cancer cells are formed because the cells don't naturally die and just continue growing. Cancer isn't caused by germs, like colds which mean you cannot catch it from someone who has it. You can talk to, and hug someone with cancer.
Cancer symptoms depend on where the cancer cells originated and where it has spread. Few cancers can be felt through the skin like for instance a lump on the breast. A change in a mole or wart on the skin often indicates melanoma (also known as skin cancer). White spots on the tongue or white patches inside the mouth usually a symptom of oral cancer.
Other cancers have less visible symptoms. Some brain tumors symptoms occur in the early stage because they affect vital cognitive functions. The symptoms of pancreas cancer usually occur in the later stage when the cancer cause pain by pushing the nerves around it or get in the way with liver function causing jaundice or the yellowing of the eyes and skin. Symptoms can also occur when the tumor pushes against blood vessels and organs. Take for example, colon cancers direct to signs such as diarrhea, constipation, and changes in stool size. Prostate or bladder cancers can cause irregular urination.