Oral cancer, also known as mouth cancer, is a type of head and neck cancer and is any cancerous tissue growth located in the oral cavity. The term oral cancer includes cancers of the mouth cancer and the pharynx. Several types of tissue make up the mouth and oropharynx. Each tissue consists of several types of cells. Cancer can develop from any of these cell types. It is important to know what kind of cancer and how it is treated. More than 9 out of 10 mouth and oropharyngeal cancers are squamous cell carcinoma. Diet low in vitamin A has been linked to oral cancer, in some studies Iron deficiency associated with Plummer-Vinson syndrome causes an elevated risk for squamous cell carcinoma of the esophagus, oropharynx and posterior mouth. Most cases of mouth cancer are linked to tobacco and alcohol. Cigarette, cigar and pipe smoking are the main forms of tobacco use in many parts of the world.