Skin cancer is a disease in which malignant cancer cells are found in the outer layers of the skin. Skin cancer is the most common type of cancer in the U.S., affecting more than 1 million people each year.

The skin has two main layers - the outer layer called the epidermis and the inner layer called the dermis.

The outer layer contains three kinds of cells - squamous cells which are flat, scaly cells in the surface, basal cells which are round cells located under the squamous cells and...