Genetic Changes May Dictate Course of Acute Myeloid Leukemia

May 1 -- WEDNESDAY, April 30 (HealthDay News) -- Breakthroughs in understanding the extremely fine genetic underpinnings of acute myeloid leukemia may allow doctors to quickly decide which existing therapies will most benefit individual patients.

"This can now help the bedside physician pick a course of action" using existing drugs, said Dr. Barton Kamen, chief medical officer of the Leukemia & Lymphoma Society. "It's telling us, with the tools we have at hand, who needs more [therapy] and where the risk is worth it."

Eventually, added Kamen, pharmaceutical companies may be able to produce drugs to specifically target the genetic mutations identified in two new studies published in the May 1 issue of the New England Journal of Medicine.

Acute myeloid leukemia, or AML, is a cancer of the bone marrow that is diagnosed in about 13,000 people in the United States each year. The incidence of the disease increases with age, while the survival rate decreases. Only 10 percent of people with AML over the age of 60 will survive two years, according to Kamen.

Scientists used to see eight kinds of AML under the microscope, but with advances in genetic knowledge, they now realize there are many more forms of the disease.

In about half of AML patients, chromosomal changes help guide doctors to select specific therapies. Deciding which treatments are best for the remaining half of patients whose cancers don't have chromosomal abnormalities remains a challenge.

"We don't know whether they will do well or not with current treatment," said Dr. Guido Marcucci, lead author of one of the studies and associate professor of medicine at Ohio State University's Comprehensive Cancer Center. "That is why we and other groups are looking at genetic mutations or changes in [gene] expression to predict the outcome of patients with no chromosomal abnormalities."

Marcucci and his team analyzed bone marrow and blood samples of 64 patients with AML who were younger than 60 and had leukemia cells with normal-looking chromosome structure. The goal: To see if microRNA profiles might help determine which treatments were best suited for which patients, and which patients were most prone to relapse.