Spectral Karyotyping Detects Chromosome Damage Linked to Smoking and Lung Cancer

Spectral karyotyping (SKY) detects chromosome damage in bronchial cells of smokers and patients with lung cancer.

Lung cancer is the leading cause of cancer deaths in the United States and kills more people than the next three most common cancers--colon, breast, and prostate--combined. Smoking is the primary risk factor for lung cancer but a number of lung cancer patients have never smoked. Quitting smoking only gradually reduces the risk of lung cancer because much of the genetic damage done by tobacco is irreversible.

The genetic changes that accompany lung cancer are not random, but are associated with specific chromosomal instabilities that may be indicative of future carcinomas. Marileila Varella-Garcia, M.D., and colleagues of the University of Colorado Health Sciences Center (UCHSC; Denver, CO, USA) used SKY to examine the bronchial epithelium (BE) of 71 subjects--14 patients with lung cancer, 43 smokers at high risk for developing lung cancer, and 14 healthy nonsmokers--in the hope of identifying underlying genetic changes that might be hallmarks for cancer. They found a marked difference between the chromosomal abnormality index (CAI) of never-smokers and that of high-risk smokers and patients with lung cancer.

"There's a tremendous amount of chromosomal damage in smokers who don't yet have cancer,” said Dr. Wilbur Franklin, professor of pathology at the University of Colorado Health Sciences Center. "Chromosomal abnormalities were observed in 82% of high-risk smokers and in all patients with carcinoma, regardless of their self-reported tobacco exposure.” Patients with cancer and high-risk smokers had nearly 23 and 15 times more chromosomal abnormalities, respectively, than never-smokers.

The study, which could pave the way toward screening people at risk for lung cancer for genetic changes that foreshadow malignancies, appeared in the September 1, 2007, issue of the American Journal of Respiratory and Critical Care Medicine.


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