Cancer can affect any part the mouth or oral cavity including the lips, tongue, gum tissue, cheek lining, floor and roof of the mouth.

Tobacco and alcohol are known to cause mouth cancer. Heavy smokers have a 20 - times greater risk and heavy alcohol drinkers have a 5 - times greater risk of develop ing mouth cancer. Those who smoke and drink heavily have a 50 - times greater risk. Chewing betel nut or areca nut , alone or in combination with tobacco and other products , also increases the risk of cancer. Prolonged sun exposure, known to cause skin cancer, increases the risk of lip cancer especially in the lower lip. More recently sexually aquired human papillomaviruses (HPV) have been shown to be a risk factor for oral cancer.

In the mouth, there are also associations between potentially malignant disorders such as leukoplakia (white patch), lichen planus and mouth cancer.