Oral cancer, also called mouth cancer, forms in the oral cavity, which includes all parts of your mouth that you can see if you open wide and look in the mirror. Your lips, gums, tongue, cheeks, roof or floor of the mouth. Oral cancer forms when cells on the lips or in the mouth mutate.

Medical concept as a mouth with Oral Cancer, malignant disease cells with 3D illustration elements.
Oral Cancer
Mouth cancer refers to cancer that develops in any of the parts that make up the mouth (oral cavity). Mouth cancer can occur on the:
- Lips
- Gums
- Tongue
- Inner lining of the cheeks
- Roof of the mouth
- Floor of the mouth (under the tongue)
Cancer that occurs on the inside of the mouth is sometimes called oral cancer or oral cavity cancer.
Mouth cancer is one of several types of cancers grouped in a category called head and neck cancers. Mouth cancer and other head and neck cancers are often treated similarly.
Symptoms
Signs and symptoms of mouth cancer may include:
- A lip or mouth sore that doesn’t heal
- A white or reddish patch on the inside of your mouth
- Loose teeth
- A growth or lump inside your mouth
- Mouth pain
- Ear pain
- Difficult or painful swallowing
Causes
Mouth cancers originate when cells in the mouth or on the lips experience DNA changes (mutations). The instructions that inform a cell what to do are encoded in its DNA. When healthy cells stop growing and dividing, mutations tell the cells to keep doing so. A tumor might develop when the abnormal mouth cancer cells accumulate. They may eventually expand from the inside of the mouth to other parts of the head, neck, or the entire body.
Mouth cancers most commonly begin in the flat, thin cells (squamous cells) that line your lips and the inside of your mouth. Most oral cancers are squamous cell carcinomas.
It’s not clear what causes the mutations in squamous cells that lead to mouth cancer. But doctors have identified factors that may increase the risk of mouth cancer.
Prevention
There’s no proven way to prevent mouth cancer. However, you can reduce your risk of mouth cancer if you:
- Stop using tobacco or don’t start. If you use tobacco, stop. If you don’t use tobacco, don’t start. Using tobacco, whether smoked or chewed, exposes the cells in your mouth to dangerous cancer-causing chemicals.
- Drink alcohol only in moderation, if at all. Chronic excessive alcohol use can irritate the cells in your mouth, making them vulnerable to mouth cancer. If you choose to drink alcohol, do so in moderation. For healthy adults, that means up to one drink a day for women of all ages and men older than age 65, and up to two drinks a day for men age 65 and younger.