Oral cancer describes cancers that originate in the oral cavity.
The oral cavity includes the lips, the gingiva, or gums, the floor of the mouth, the buccal mucosa which is the soft lining of the inner lips and cheeks, the anterior or front two-thirds of the tongue, the hard palate which is the tough front part of the roof of the mouth, and the retromolar trigone which is the mucosa right behind the last molars on the bottom row of teeth.
Behind the oral cavity is the oropharynx.
The oropharynx includes the soft palate which is the soft part of the roof of the mouth right behind the hard palate, the tonsils, the walls of the throat, and the posterior or back one-third of the tongue.
The oral cavity and oropharynx are lined by epithelium - and there are a few different types.
The first type of epithelium is called keratinized stratified squamous epithelium.
These epithelial cells produce keratin, a protein that makes the layer tough, and protects against normal wear and tear from food and drinks.
Beneath the epithelium, there’s another layer called the basement membrane made of tough connective tissue, and below that is the lamina propria which yet more connective tissue that houses blood vessels, lymphatics, nerves, and immune cells.
The oral surfaces covered in keratinized epithelium include the hard palate, the dorsal surface, or top, of the tongue, and the gingiva.
A second type of epithelium is non-keratinized stratified squamous epithelium, and it contains cells that don’t produce much keratin, making this layer less tough.