Although lung cancer kills more men and women than breast, prostate and colon cancers combined, effective treatments for this disease remain elusive, as does implementation of a national screening program.
Now, City of Hope Cancer Center researchers have developed a method for isolating and identifying genes associated with lung cancer. The technique could lead to better risk prediction and earlier diagnosis of the disease. Their work, presented April 3 at the annual meeting of the American Association for Cancer Research, focuses on the methylation status of specific sections of DNA, where measurable changes in molecular structures specific to cancer development occur.
CpG islands, areas in the DNA strand where there are high concentrations of specific nucleotides, are associated with the activity of cancer-related genes and become methylated during tumor development. Tibor Rauch, Ph.D., postdoctoral research fellow in the Division of Biology, and Gerd P. Pfeifer, Ph.D., professor and chair of the Division of Biology, isolated the genetic markers with a methyl-CpG recovery assay (MIRA) they developed.
“This is a powerful and effective method to isolate genes and determine whether they are indicative of tumorigenesis and the development of lung cancer,” said Rauch. Current efforts at early detection, including chest X-rays, analysis of mucus cells, and fiberoptic examination of bronchial passages in the lungs, have shown limited effectiveness in improving survival rates for lung cancer patients. However, new procedures using low-dose spiral computed tomography scans and research into molecular markers have demonstrated promising results in clinical trials.
“We hope to develop a MIRA-based screening method that will enable us to detect and diagnose lung cancer at earlier stages,” added Rauch.
At 15 percent, the five-year survival rate for lung cancer is much lower than that of breast and prostate cancers - 88 percent and nearly 100 percent, respectively - for which proper screening tests exist. Of the more than 170,000 cases of lung cancer diagnosed each year, only 16 percent are identified at an early, more operable stage when survival is better (50 percent over five years). City of Hope treats nearly 300 lung cancer patients each year.
