New understanding of chronic myeloid leukemia

Oregon Health & Science University Cancer Institute researchers have opened a new window into the roots of chronic myeloid leukemia (CML).

“We are looking under the surface of CML to understand better where the cancer is coming from. We have discovered abnormal cells in the early stem cell population in some CML patients, which don't belong to the CML clone. These are abnormal cells that are not part of the CML clone,” said Thomas Bumm, M.D., OHSU Cancer Institute member.

This research was presented at the American Society of Hematology annual meeting in Atlanta on Sunday, Dec. 9.

Bumm was looking into Philadelphia Chromosome-negative stem cells – which he and others had thought would look like normal, healthy cells, and have normal chromosomes. (It has been known that the driving force of CML is the Philadelphia Chromosome-positive cancer cells.)

“But no, these chromosome negative cells are not normal looking. We are seeing that there are other abnormal cells in the early stem cell population in the bone marrow of some CML patients that are Philadelphia Chromosome-negative. They have abnormalities such as the deletion of chromosome 7 or a duplication of chromosome 8,” explained Bumm, a fellow in hematology/medical oncology, OHSU School of Medicine.

It is not known why patients with CML have these abnormal cells and to what extent. These newly discovered abnormal cells are also seen in other cancers such as myelodysplastic syndrome.

“We are not yet sure about the extent of this problem. We do hope though that our studies into the stem cell compartment of CML patients might help to find new targets for CML therapy to cure this cancer,” Bumm said.

Chronic myelogenous leukemia is a form of blood cancer characterized by the increased and unregulated growth of predominantly myeloid cells in the bone marrow and the accumulation of these cells in the blood.

The next step, although costly, will be to analyze more leukemia patients as well as healthy bone marrow samples to continue to look for these new abnormalities.