Chemical messengers in the body that send information between cells and control the actions of certain cells and organs.

…but can occur anywhere on the body. Skin has several layers. Skin cancer begins in the epidermis (outer layer), which is made up of squamous cells, basal cells, and melanocytes. There are several different types of skin cancer. Squamous cell…

The process of glandular cells undergoing changes to become squamous cells….

Cancer starts when cells begin to grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas of the body. To learn more about how all cancers start and spread,…

Part of the body’s immune system. Antibodies are proteins made by the blood in response to an invader (antigen) in the body. They help protect against viruses, bacteria and other foreign substances.

Measurements of the body’s pulse rate, temperature, respiration rate, and blood pressure. This indicates the state of essential body functions….

The system that removes wastes from the blood and expels them from the body in urine. It includes the kidneys, ureters, bladder and urethra….

A small machine, usually attached to a finger or toe, that measures how much oxygen is in the blood….

A condition in which red blood cell levels are higher than normal….

A specialist who studies diseases to understand their nature and cause, and who interprets the results of tests (such as a biopsy or blood count)….