Scientists in China have identified a gene variant which appears to protect Chinese people from various types of cancer.

In the latest issue of the journal Nature Genetics, the experts said they had studied the DNA of nearly 10,000 Chinese people and had found that the gene variant appeared far more frequently in those who were cancer-free.

"We have identified a variant of the CASP8 gene that appears to be associated with lower risk of lung, oesophageal, gastric, colorectal, cervical and breast cancers in Chinese people," Lin Dongxin of the Chinese Academy of Medical Sciences in Beijing wrote in an e-mail to Reuters.

It is well known that the gene caspase-8 (CASP8) regulates cell death. Programmed cell death, or apoptosis, is important because it prevents cells from dividing and spreading uncontrollably, a process that can result in cancer.

However, scientists know little about the variants of this gene and the roles they play in cancer susceptibility.

Between January 1997 and July 2003, researchers in various cancer institutes in Beijing examined the DNA of 5,000 patients with lung, oesophageal, colorectal, cervical, stomach and breast cancer, and 4,972 others who were cancer-free.

The gene variant showed up in 25 percent of those who were cancer-free, and in 20 percent of those who had cancer.

Explaining how this gene variant might have benefited its carriers, Lin said: "Carriers may have lower apoptotic cell death of T lymphocytes (white blood cells) when they fight with malignant or premalignant cells."

"The immune status is very important in cancer development, and genetic variation in the immune system is associated with predisposition to cancer," Lin said.

The discovery may help identify high-risk individuals. 

"The genetic variant we identified might (serve) as a genetic marker in identifying high-risk individuals, which is an important step in targeted prevention and early detection of human cancer," Lin said.

Cancer is a leading cause of death worldwide. It accounted for 7.6 million, or 13 percent, of a total of 58 million deaths worldwide in 2005, according to the World Health Organization.

WHO projects that figure rising to nine million in 2015 and 11.4 million in 2030.

(Shanghai Daily April 24, 2007)