An international research group believes it has discovered why some ethnic groups are more susceptible to alcohol-induced cancer than others.The project has discovered the existence of a gene in certain groups that stops the body getting rid of an alcohol by-product, which may make saliva act as a carcinogenic. The findings, published in the journal Alcoholism: clinical and experimental research, says that when the body tries to break down alcohol there are two stages. The first is the chemical breakdown of alcohol into acetaldehyde. The second is the conversion of acetaldehyde into acetate, which the body can more easily deal with.Some people lack the genetic code that lets the liver make the second chemical. These people have far more acetaldehyde in their bodies than people who have the necessary gene. Scientists believe that the more people drink the more acetaldehyde is found in the saliva, which can cause cancer as it passes across the throat tissue.As many as 50% of Chinese and Japanese people lack the gene. The excess acetaldehyde causes symptoms when they drink like facial flushing, dizziness and nausea. If these people drink more heavily, there is more of the toxic chemical found in their saliva than those who produce the gene.The study found that in the gene-deficient Asians, acetaldehyde levels in the saliva were two to three times higher than either Caucasians, or Asians who had the gene. Chris Brook-Carter