Squamous epithelia form the lining surface of tissues in contact with the environment: the skin, oral mucosa, esophagus and respiratory tract, the genital tract, and several other specialized tissues. These tissues are at highest risk for exposure to environmental carcinogens such as UV, tobacco smoke and infectious agents. Cancers that form in squamous epithelia are among the most common human solid tumors and have high morbidity and mortality. These cancers include squamous cell carcinoma of the skin, oral cancer, head and neck and esophageal cancer, certain lung cancers and cervical...