Mouth cancer is the sixth more popular and dangerous type of cancer in the world, affecting about 30,000 people yearly. It is most common in middle aged people and in elders, while young people are less likely to develop oral cancer. However, heavy drinking and smoking represent the main causes of oral cancer, therefore young individuals are not that safe, as they could develop this cancer type later in life as a consequence of youth bad habits. Smoking and drinking damage DNA and lead to various types of cancer, including mouth cancer.

Oral cancer patients develop malignant tumors in any part of the mouth - tongue, gums, lips, upper or lower jaw and throat. The cancerous tumor appears in the mouth as a red or white lump that does not heal and bleed easily for more than a month. Subsequent symptoms consist in problems in moving the tongue, jaw, swallowing, chewing and other actions typical for the mouth.

However, scientists at the Beatson Institute for Cancer Research in Glasgow, Scotland, showed that there are two types of oral tumors which differ in severity. Namely, there are cancer cells that can die naturally and do not produce significant harm to an individual's life and cancerous cells that proliferate and lead to one's death if not prevented and treated adequately.

Prof. Paul Harrison from the Scottish Beatson Institute stated: "The data we collected provide strong evidence for the first time that some mouth cancer tumors are more aggressive than others and therefore linked to poor patient survival."

Therefore, there are oral tumors that can be naturally annihilated by our immune system and there are dangerous mouth tumors that keep dividing uncontrollably, leading to cancer. Scientists showed that the dangerous tumors that may lead to severe health impairment usually present faulty p53 and p16 genes. The former gene prevents damaged cells from dividing, while the latter regulates cells.

The discovery is very important because it will help doctors decide which the people at higher risk from mouth tumors are. They will be able to treat patients differently, in order to cut on severe health problems caused by oral cancer.