If you paid any attention at all in your elementary-school health class, you'd know by now that smoking a lot leads to lung cancer and chronic obstructive pulmonary disease (COPD). But what leads some people to smoke more than others? An international team of researchers, led by two professors at Washington University Medical School, thinks it has an answer, and it all comes back to Chromosome 15.
A survey of 38,000 smokers worldwide showed that people with the same variants of two groups of genes on Chromosome 15 have greater tendencies not just to develop lung cancer and COPD but also to be addicted to nicotine. The strange part is not that nicotine addiction leads to more smoking which leads to lung disease but that the genes that control lung disease and nicotine addiction are located on the same chromosome.
"There's a reward center in the brain," Dr. Laura Jean Bierut, one of the investigators, said in a press release. "The center becomes activated with addiction, and the gene is clearly active in that brain region. But the gene also functions in the lung, meaning we need to ask the question of whether this gene is both driving the pathology of addiction in the brain while also working in the lung to contribute to COPD and cancer."
The results of the study will appear in the journal Public Library of Science (PLoS) Genetics. Bierut and her fellow researchers hope their work will inspire other scientists to examine multiple factors at once.
"Previous studies have shown associations between gene variants and smoking," said Nancy Saccone, another Wash. U. professor who is the lead author of the study. "The important finding from our analysis is that a new group of variants also is associated with smoking behavior, further highlighting this area as an important target for follow-up studies to better understand the mechanisms underlying those associations we observed."