Another study of p53 expression in oral squamous cell carcinoma determined that cats exposed to any environmental tobacco smoke were four and a half times more likely to overexpress p53 in their tumors than were unexposed cats. 8 The p53 protein, the product of a tumor suppressor gene, regulates cell growth and proliferation and prevents unrestrained cell division after chromosomal damage. Abnormal p53 accumulates in the cell, unlike normal, wild-type p53, and can be detected via immunohistochemistry. The absence of functional p53 increases the risk of developing various cancers, and it is suggested that p53 may be a possible site for carcinogen-related mutations within some squamous cell carcinomas. 8
This is now generally considered an early, noninvasive stage of squamous cell carcinoma. It appears as a persistent red-brown, scaly patch that may resemble psoriasis or eczema. If untreated, it may invade deeper structures. Bowen’s disease is most often caused by exposure to the sun or to arsenic, but radiation and other chemical carcinogens, genetics and trauma also may play a role. The human Papillomavirus (HPV), highly transmissible through sexual contact, has been documented as a cause of one form of Bowen’s disease affecting the genitals. HPV can also arise in the mucous membranes of the nose and mouth as well as on the skin. The FDA approved an HPV vaccine for use by females aged 9–26 in 2006, and one for 9-26-year-old males (as well as another vaccine for females) in 2009. The vaccines areconsidered highly effective in preventing HPV and thereby reducing the risk of both genital warts and cervical cancer as well as Bowen’s disease.