Genes may increase risk of smoking-related cancer

Individuals with alterations in ABCB1 and ABCC1, two genes thought to be involved in getting rid of inhaled toxins from the lungs, may have an increased risk of developing lung cancer, according to a new study published in the journal Cancer. The research, carried out by Chinese and American scientists, may help to explain why some smokers succumb to the disease while others manage to evade it, despite a lifetime of heavy smoking.

The researchers, led by Daru Lu and Haijian Wang of the Fudan University in Shanghai, studied DNA samples from 500 patients with lung cancer and compared it with that of 517 cancer-free patients in south eastern Chinese population. They found that variations in two genes were more common among the cancer patients than among the control group. Thirty-one per cent and 27 per cent of the cancer patients carried certain variations in the ABCB1 and ABCC1 genes respectively, compared to 15 per cent and 12 percent 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.

Dr Wang and his team have previously published findings concerning other gene variants associated with an increased lung cancer risk - such as the genes CYP2A13 and ADRB2 - supporting the theory that genes, as well as environmental factors such as smoking, play a significant role in the development of the disease.

The researchers hope that the discovery of other common gene variants linked to lung cancer will lead to a better understanding of how to prevent and treat the disease. 'Because tobacco smoking is the leading preventable cause of cancer and the cancer-prone genotypes of these genetic components are relatively prevalent in the human population, our findings have important implications for the prevention of tobacco smoking-related cancers', the authors wrote.