May 17, 2011 | Basal and squamous cell skin cancers are also known as keratinocyte cancers because they develop from cells called keratinocytes, the most common cells in the skin. Squamous cells lie just below the outer surface and function as the skin’s inner lining while basal cells, which produce new skin cells, lie just beneath the squamous cells. Both basal cell and squamous cell cancers are found mainly on parts of the body that are exposed to the sun, such as the head and neck, and their occurrence is related to the amount of sun exposure a person has had. These cancers, especially basal cell cancers, rarely spread elsewhere in the body and are less likely to be fatal. Still, it is important to recognize them. If left untreated, they can grow quite large and invade into nearby tissues, causing scarring, disfigurement, or even loss of function in some parts of the body. It is important for doctors to tell these types of skin cancer apart, because they are treated differently.