AML is the most common acute form of leukemia in adults. In devising a treatment plan, a doctor relies on indicators such as how the cancer cells look under a microscope as well as the patient's age and disease history to decide how aggressive the cancer is likely to be. But for some patients, those indicators aren't enough to place them in a high-risk or low-risk group, and doctors may be left guessing which treatments to try.
"This intermediate-risk group poses the biggest problem for assigning treatment," said Jonathan Pollack, MD, PhD, assistant professor of pathology, who led the study. For AML, Pollack said it's particularly important to know how to treat the cancer because aggressive forms often relapse after chemotherapy. Treatments such as stem cell transplants, on the other hand, are considered too risky for patients with less aggressive forms of the disease.
In the study, Pollack's colleagues in Germany collected tumor samples from 116 adults with AML, including 45 with an intermediate-risk form of the disease. Lars Bullinger, MD, then a postdoctoral scholar in Pollack's lab, used a technique called microarray analysis to take a snapshot of the activity level of 26,260 genes in each sample. From this, the researchers found two distinct patterns of which genes were turned on or off. These patterns correlated with how long the intermediate-risk patients lived after diagnosis. Those in the first group lived on average about twice as long as those in the second group.