HONG KONG - RESEARCHERS in China and the United States have identified mutations of two genes which appear to make ethnic Chinese more susceptible to lung cancer, they wrote in the journal Cancer.

Their finding involves two genes, ABCB1 and ABCC1, which were previously thought to be linked to eliminating carcinogens from the lungs and protecting them against inhaled toxins.

In their study, the researchers analysed the genes of 500 patients with lung cancer and 517 cancer-free participants in south-eastern China.

'The investigators found that certain (gene) variants were found much more often in individuals with lung cancer than in cancer-free controls,' they wrote in a statement.

Among those with cancer, 31 per cent were found with a certain mutation of the ABCB1 gene, while 27 per cent were found with a variant of the ABCC1 gene.

But those same mutations were found in only 15 per cent and 12 percent of participants in the cancer-free group.

'The variant (of ABCB1) was particularly associated with an increased risk of cancer in women and in individuals under age 60 years. It also was linked to a major type of lung cancer called adenocarcinoma,' the researchers said.

Another study published in the Lancet in October predicted that China would see 65 million deaths from chronic obstructive pulmonary disease (COPD) and 18 million deaths from lung cancer between 2003 and 2033 from smoking and biomass burning at home.

Those figures would account for 19 and 5 per cent respectively of all deaths in China during that period, said the researchers at the Harvard School of Public Health (HSPH).

Respiratory diseases are among the 10 leading causes of deaths in China. About half of Chinese men smoke. In more than 70 per cent of homes, Chinese cook and heat their homes with wood, coal and crop residues. -- REUTERS