Gene flaws may hold clue to high rate of cancer
Flaws in three genes could help explain why parts of southern China have extraordinarily high rates of a type of nose-and-throat cancer, according to a recent discovery by international scientists.
The discovery could help identify high-risk groups so that they can go for regular cancer screening and the disease can be discovered as soon as possible, a local academic said.
Nasopharyngeal carcinoma (NPC), a cancer that forms in the lining of the upper throat lying behind the nose, is more likely to occur in the southern parts of China than in the rest of the world. It is dubbed the "Cantonese cancer".The cancer occurs here in about 25 cases per 100,000 people, 25 times higher than the rest of the world.
The research was led by the Genome Institute of Singapore and the Sun Yat-Sen University Cancer Centre in Guangzhou, and involved scientists from the mainland, Singapore and the United States.
In the study, 10,000 people of southern-Chinese descent were selected and compared through the help of a genetic database.
Half of the volunteers had been diagnosed with NPC, while the other half were healthy. What showed up in the cancer group were telltale variants in three genes, according to the research, published in the latest issue of the journal Nature Genetics.
The three, named TNFRSF19, MDSIEVI1 and CDKN2A/2B, have been previously linked with leukaemia. The latter two genes were associated with immunity.Another pointer in the cancer patients was a variation in the leukocyte antigen (HLA) gene, which has previously been suspected.
The findings were seen as important as they could shed light on the molecular pathways of NPC and its high prevalence in southern China, especially Guangdong.
Chinese University clinical oncology professor Tao Qian said that with the new discovery, doctors could predict who had a higher chance of developing NPC, and these people could be sent to cancer screenings every three to six months.
"As long as cancers are discovered early, there is a high chance that the patients can be cured," he said.
He said that as well as genetic flaws, the disease had also been associated with the consumption of food rich in sodium, in studies.
The disease might have been more common in southern China because Cantonese people were more likely to eat salted fish and preserved vegetables, he said.
Another hypothesis, he said, was that the Epstein-Barr virus with which NPC was associated was different among Cantonese from the rest of the world. The virus is one of the most common in humans.
He said eating more fresh vegetables and avoiding smoking and alcohol, could help prevent NPC.
Only Alaska, parts of northern Africa and southeastern Asia have similarly high rates of NPC.
Source: http://www.scmp.com
