The effects of smoking cigarettes on gene activity have been investigated in the largest study of its kind. Researchers writing in the open access journal BMC Medical Genomics studied white blood cells taken from 1,240 people to identify 323 unique genes whose expression levels were significantly correlated with smoking behavior.
Jac Charlesworth led a team of researchers from the Southwest Foundation for Biomedical Research, Texas, USA, who carried out the study as part of the long running San Antonio Family Heart Study in families from the Mexican American community in San Antonio. She said, "Previous studies of gene expression as influenced by smoking have been seriously limited in size with the largest of the in vivo studies including only 42 smokers and 43 non-smokers. We studied 1,240 individuals, including 297 current smokers. Never before has such a clear link between smoking and transcriptomics been revealed, and the scale at which exposure to cigarette smoke appears to influence the expression levels of our genes is sobering".
Within the smoking population, the researchers identified significant changes in the expression of genes within a range of categories that correspond well with known smoking-related pathologies, including immune response, cell death, cancer, natural killer cell signaling and metabolism of foreign particles. According to Charlesworth, "Our results indicate that not only individual genes but entire networks of gene interaction are influenced by cigarette smoking. It is likely that this observed effect of smoking on transcription has larger implications for human disease risk, especially in relation to the increased risk of a wide variety of cancers throughout the body as a result of cigarette smoke exposure".