New biomarker that may help predict leukemia aggressiveness identified

Washington, Apr 20 (ANI): Scientists from University of California, San Diego and the Moores UCSD Cancer Centre have identified a biomaker that may help predict aggressiveness of difficult-to-treat form of leukaemia.

The research team, led by Dr Paul A. Insel, professor of pharmacology and medicine at the UC San Diego School of Medicine, has found that high levels of a enzyme, called PDE7B, in the blood are an indicator that chronic lymphocytic leukemia (CLL) - the most common form of adult leukaemia.

In the previous study, Insel's group had discovered that among a group of enzymes, cyclic nucleotide phosphodiesterases, one of the phosphodiesterases, PDE7B, was 10 times higher in CLL patients than in healthy individuals. PDE7B controls the levels of cyclic AMP (cAMP), a molecule that can promote programmed cell death, a process that is defective in CLL.

"The question was, could the level of PDE7B expression provide evidence for the clinical stage and diagnosis for individual patients?" Insel said.

During the study, Insel along with postodoctoral fellow Linghzi Zhang, compared the amount of PDE7B in white blood cells in 85 untreated patients with CLL to those of 30 healthy adults, and watched for changes over time.

"We found that individuals with high levels really had worse disease and showed that PDE7B expression had predictive value relative to other currently available markers for disease severity and progression," Insel said.

"In some cases, the level of PDE7B expression provided prognostic information that was additive to existing markers," he added.

Zhang said that PDE7B can be used alone as a biomarker for CLL if the levels are high enough, but may be used with other markers if the level is lower and ambiguous.

"PDE7B may not be good enough by itself if it's not high enough. If it is low, other markers could be helpful," she said.

Insel said that their research to date implies that PDE7B has a role in prognosis and could also be a good drug target because it reflects part of the biology of the disease.

"This implies that if we can develop drugs to block this enzyme, which would raise cAMP and promote apoptosis - which is really at the heart of the underlying pathology," he added.

The study was presented at the AACR 100th Annual Meeting 2009 in Denver. (ANI)