Mouth cancer can develop in any part of the mouth, including the tongue, the gums, the lining of the mouth, or the lips. It is more common in men than in women.

Cancers of the mouth are rare in people under the age of 40. These cancers are usually clearly visible when you look in someone's mouth. In their early stages they are often completely painless. The signs can be any of the following:

• A sore, or ulcer, in the mouth that does not heal
• White patches that do not go away, anywhere in your mouth
• Red patches that do not go away, anywhere in your mouth
• A lump on the lip, tongue or in the mouth or throat

All these symptoms do have other causes, but if your father does have any of these then it would be very wise for him to see his family doctor for a check up, to make sure he is not developing a mouth cancer. This is very important because early cancers of the mouth can easily be cured.

Mouth cancer is more common in India (and other parts of Asia), where it is often caused by chewing paan.

(Paan, or betel quid, is a mixture of areca nut, lime and other spices wrapped in a betel leaf. It is also available as Paan masala, a readymade packet that may contain either the whole mixture or just the spices. Paan is often combined with tobacco, and this increases the cancer risk even more.)