PTH controls calcium and phosphorus levels in the blood. PTH is made by the parathyroid glands, which are four pea-sized glands that lie behind the thyroid gland. If the blood calcium level is too low, the parathyroid glands release more PTH.
Skin cancer is a cancer of the cells in the outermost layer of skin, called the epidermis. The epidermis itself has three layers: an upper and middle layer made up of squamous cells, and a bottom layer made up of melanocytes and basal cells.
Learning About Skin Cancer. Skin cancer is the most common type of cancer in the United States. An estimated 40 to 50 percent of Americans who live to age 65 will have skin cancer at least once. The most common skin cancer is basal cell carcinoma, which accounts for more than 90 percent of all skin cancers in the United States.