May 31, 2012 — Lung cancer makes up only 15 percent of cancer diagnoses, but it is the leading cause of cancer deaths. To help doctors detect the disease in its early, most treatable stages, epidemiologists like Margaret Spitz, a professor at Baylor College of Medicine, are working to develop models of genetic, environmental, and behavioral factors to identify patients at greatest risk. Spitz told the audience at Harvard School of Public Health’s 155th Cutter Lecture on Preventative Medicine on May 9, 2012 that the future of cancer epidemiology lies not only in the genetics laboratory but also in the rigorously designed population study—and in getting researchers in both camps to work together.
Spitz champions “integrative epidemiology,” which brings together the latest methods for identifying the genetic variants associated with increased disease risk and the traditional sampling and statistical techniques epidemiologists use to identify patterns in populations. She described new research identifying genes associated with both a risk for nicotine dependency and lung cancer and genes linked to increased risk for obesity, but noted that as of yet the genetic models alone have no diagnostic value.
Despite all that has been learned since the human genome was mapped in 2003, many questions remain to bedevil scientists. Now that intriguing genetic variants have been identified, more work needs to be done to elucidate the ways in which these genes and the environment interact, Spitz said. One variant of interest is what scientists call the “thrifty gene,” which is more prevalent in populations that are currently prone to obesity but have a history of food scarcity. A gene that may once have helped people survive lean times could be causing their descendants to pack on the pounds, Spitz said.
The jury is still out on the hereditability of lung cancer, Spitz said. But the identification of gene variants associated with smoking intensity does show more immediate promise for identifying smokers who will need extra help to quit. Some smokers are genetically prone to become more dependent on nicotine than others and require a higher number of cigarettes to maintain an acceptable level. Those heavy smokers will have a harder time quitting, Spitz said.
Michelle Williams, chair of the Department of Epidemiology and Stephen B. Kay Family Professor of Public Health Chair, and Lorelei Mucci, associate professor of epidemiology, gave opening remarks. Williams described Spitz’s lecture as “high art” that “encapsulates where we are and where we can go.”
Photo: Aubrey LaMedica