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.
Skin Cancer Information. En EspaÃ±ol. What Is Skin Cancer? Skin cancer is the uncontrolled growth of abnormal skin cells. It occurs when unrepaired DNA damage to skin cells (most often caused by ultraviolet radiation from sunshine or tanning beds) triggers mutations, or genetic defects, that lead the skin cells to multiply rapidly and form malignant tumors.