Squamous cell carcinoma (SCC) is an uncontrolled growth of abnormal cells arising in the squamous cells, which are made up of most of the skin’s upper layers. SCCs frequently look like scaly red patches, open sores, elevated growths with a central depression, or warts; they may crust or bleed. SCC is generally caused by cumulative UV exposure over the course of a lifetime. It can become disfiguring and sometimes deadly if allowed to grow. An estimated 700,000 cases of SCC are diagnosed each year in the US, resulting in approximately 2,500 deaths.

SCCs may arise on all areas of the body including the mucous membranes and genitals, but are most familiar in areas commonly exposed to the sun, such as the rim of the ear, lower lip, face, bald scalp, neck, hands, arms and legs. Often the skin in these areas reveals telltale signs of sun damage, such as wrinkling, changes in pigmentation, and loss of elasticity.

The most hazardous form of skin cancer, these cancerous growths progress when unrepaired DNA damage to skin cells triggers mutations (genetic defects) that lead the skin cells to multiply rapidly and form malignant tumors. These tumors originate in the pigment-producing melanocytes in the basal layer of the epidermis. Melanomas often resemble moles; some develop from moles. The majority of melanomas are black or brown, but they can also be skin-colored, pink, red, purple, blue or white. Melanoma is caused mainly by intense, occasional UV exposure, especially in those who are genetically predisposed to the disease. Melanoma kills an estimated 8,790 people in the US annually.

If melanoma is recognized and treated early, it is almost always curable, but if it is not, the cancer can advance and spread to other parts of the body, where it becomes hard to treat and can be fatal. While it is not the most common of the skin cancers, it causes the most deaths. About 120,000 new cases of melanoma in the US are diagnosed in a year.