SNPwatch: Variants in Genes for Carcinogen Transporters Linked to Lung Cancer

SNPwatch gives you the latest news about research linking various traits and conditions to individual genetic variations. These studies are exciting because they offer a glimpse into how genetics may affect our bodies and health; but in most cases, more work is needed before this research can provide information of value to individuals. For that reason it is important to remember that like all information we provide, the studies we describe in SNPwatch are for research and educational purposes only. SNPwatch is not intended to be a substitute for professional medical advice; you should always seek the advice of your physician or other appropriate healthcare professional with any questions you may have regarding diagnosis, cure, treatment or prevention of any disease or other medical condition.

When the toxins in cigarette smoke are inhaled, lung cells don’t just sit there and take it. A complex network of proteins is activated with every puff. The proteins break down, modify, or pump out as many of the hundreds of cancer-causing chemicals in tobacco smoke as possible.

But when this system fails or falls behind, toxins have a chance to damage cells. New results published online this week in Cancer show that variants in the genes for ABCB1 and ABCC1, two important pump proteins that transport a variety of toxins out of lung cells, increase the risk of lung cancer.

Haijian Wang and colleagues studied 500 lung cancer patients and 517 healthy controls from Nanjing City and the surrounding area in southeast China. They found that, overall, having one or two Cs at rs3842 in the ABCB1 gene was associated with 1.36 times increased odds of lung cancer compared to having two Ts. For rs212090 in the ABCC1 gene, having one or two As increased the odds by 1.37 times.

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Further analysis showed that the C version (one or two copies) of rs3842 increased the odds of lung cancer in women of all ages by 2.57 times and by 1.5 times in those younger than 60. The A version of rs212090, on the other hand, was not significantly associated with lung cancer in those under 60, but did increase the odds by 1.6 times in those 60 and above. In those people with a history of cancer in a first-degree relative (parent, sibling or child), the C version of rs3842 increased the odds of lung cancer by 1.91 times.

A final correlation the authors found was between the riskier C version of rs3842 in the ABCB1 gene and a specific type of lung cancer called adenocarcinoma. The authors say that the rates of this type of cancer has been increasing in the last few decades, as has the amount of a specific carcinogen in cigarette smoke that is dealt with by the ABCB1 protein.

“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 write.