CAMBRIDGE, Mass.—Clinicians can visualize growing tumors using positron emission tomography (PET) from their rapid uptake of 18F-labeled glucose (FDG). The traditionally poor resolution of microPET systems, however, prevented drug discovery researchers from using this analysis method in preclinical studies of drug candidate efficacy. Recently, scientists at Millennium Pharmaceuticals showed that the latest microPET systems could be used to monitor tumor regression in mice treated with an anticancer drug.
Describing their work in Molecular Imaging and Biology, the researchers treated SCID mice carrying human prostate cancer cells with the proteasome inhibitor bortezomib (Velcade) and used FDG-microPET and microscopy to monitor tumor response. After a short lag phase in which there was little difference between placebo and treated mice, the scientists detected a significant decrease in FDG uptake by tumors in the treatment group.
They also found that while histological examination and FDG-microPET correlated well, the latter method was much more sensitive for detecting "subclinical" responses to treatment. As such, the scientists see potential value of FDG-microPET as a noninvasive metabolic biopsy tool in the drug discovery arsenal.