Now researchers found a simple blood test may be a cheap, easy and effective way to spot risk of recurrence of a common form of acute myeloid leukemia. This type of acute myeloid leukemia is characterized by a mutation in the NPM1 gene. A third of acute myeloid leukemia patients have this form of the deadly blood and bone marrow cancer. Accurately pinpointing the highest-risk patients has proven difficult, with doctors typically forced to rely on costly and time-consuming genetic testing of extracted tumor tissue. Despite aggressive chemotherapy, a certain percentage of patients with this mutated gene will see their disease return and many would benefit from a pre-emptive, lifesaving bone marrow transplant. Sometimes called stem cell transplantation, the researchers noted. But a transplant ultimately destroys not only the marrow's cancerous cells but healthy tissue as well. So, doctors have long sought a reliable way of separating those in true need of a transplant from those who would likely fare well without one, the researchers. Minimal residual disease testing is planned to help doctors screen for patients whose post-chemotherapy blood contains a telltale sign of the NPM1 gene mutation. Those who have that sign are at high risk for recurrence of the leukemia, and need a transplant, the researchers. The test is now being used in a number of European countries.