Cancer is a group of diseases that begin in cells, the building blocks of life. Cells are essential parts of the body, and when they are damaged they can cause many problems. Under normal conditions, cells grow and divide to produce more cells when the body needs them. However, sometimes, these cells keep dividing causing a growth of tissue, which is called a tumor.
Tumors are generally benign or malignant. Benign tumors are not considered cancer and can often be removed from the body, without coming back. Benign tumors are rarely threatening to the body. Malignant tumors are cancer and the cells in these tumors are abnormal, dividing without any sort of control or order. The cells can spread and harm nearby organs; they can also enter the bloodstream, or lymphatic system, spreading to form new tumors in other organs. This spread of cancer is called metastasis. Most cancers are named after the organ they form in, for example, cancer in the lungs, is referred to as lung cancer.
Almost anyone can contract cancer, although there are certain high-risk behaviors and activities that can increase the likelihood of contracting cancer. The definitive cause of cancer has not yet been discovered, although researchers are searching for answers. Researchers also study patterns of cancer in the population to look for risk factors, conditions that increase the chance that cancer might occur. Although doctors cannot explain why one person gets cancer and another does not, it is clear that cancer is not caused by an injury, such as a bruise or bump. Although being infected with some viruses can increase the chance of getting cancer, it is not contagious, meaning it is not possible to catch it from someone else.
Cancer, generally, develops over time. Cancer is a result of a...