One of the fairly common non-melanoma types of skin cancers are basil cell carcinomas. They evolve in the cell layers between the dermis and epidermis, are rarely invasive and grow slowly. Basil cell carcinomas are found on parts of the body which are often exposed to the sun such as the scalp, face and ears. Irritation, chronic scarring, and exposure to arsenic and polycyclic hydrocarbons are known risk factors.