- MONDAY, Oct. 6 (HealthDay News) — A new technique may help doctors
diagnose a rare form of leukemia in a matter of hours instead of weeks,
researchers say.

Juvenile myelomonocytic leukemia (JMML) occurs in children; symptoms
include fevers, poor growth, and infections.

Early diagnosis of JMML is important, since the only cure is a bone
marrow transplant. But JMML is currently diagnosed by monitoring the
response of JMML cells to a growth-stimulating factor called GM-CSF, which
involves two to three weeks of growing cells in the laboratory.

Now, a new study published in the Oct. 7 issue of Cancer Cell
may have found a faster way to diagnose this relatively rare leukemia.

For their study, researchers used a new technique that builds on flow
cytometry.

In flow cytometry, fluorescently labeled antibodies are used to
classify and sort cells based on the proteins on their outer surface. The
new approach goes further by sending antibodies inside the cell to bind to
target proteins.

To find a way to diagnose leukemia, the researchers used an antibody
that binds only to the activated form of a protein called STAT5 in cell
samples of 12 patients with JMML.

Eleven of the 12 JMML cell samples displayed abnormally high levels of
STAT5 in response to low doses of GM-CSF. Seven out of the eight normal
bone marrow samples, and eight out of eight samples from patients with
similar — but not identical disorders — did not have increased levels of
STAT5 in response to GM-CSF.

“I was surprised how much more we can learn about the inner nature of
these cells by 'interrogating' them with different conditions,” senior
co-author Garry Nolan, immunologist and member of the Donald E. and Delia
B. Baxter Laboratory in Genetic Pharmacology at Stanford, said in a
university news release. “Time and again, we are finding this to be a
powerful amplifier of the fate of a diseased cell and a good way to
understand why it responds to certain treatments and not others.”

Since the new technique can help track disease progress, the
researchers hope that it can be used to monitor the effectiveness of
potential drug treatments for JMML and other disorders.

“Identifying populations of cells by their responses to specific
stimuli will facilitate our ability to assess the efficacy of specific
agents in relevant subsets with increased precision,” senior-co-author
Mignon Loh, an associate professor of clinical pediatrics at the
University of California, San Francisco, said in the release.

“In an era of using increasingly sophisticated targeted agents, we hope
that these studies will allow investigators to more fully appreciate the
specificities of their therapies,” said Loh.

More information

The American Cancer Society has more about childhood leukemia.