Variants in Genes for Carcinogen Transporters Linked to Lung Cancer

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 specific variants in the ABCB1 gene was associated with increased odds of lung cancer.

The researchers also found a variant that 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.  In those people with a history of cancer in a first-degree relative (parent, sibling or child), the researchers found a variant that increased the odds of lung cancer by 1.91 times.

A final correlation the authors found was for a specific type of lung cancer called adenocarcinoma. The authors say that the rates of this type of cancer have 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.