New Insights Into Deadly Brain Cancer
New findings by researchers at UNC Lineberger Comprehensive Cancer Center suggest that the most common form of malignant brain cancer in adults, glioblastoma multiforme (GBM), is probably not a single disease but a set of diseases, each with a distinct underlying molecular disease process. The study, published by Cell Press in the January issue of the journal Cancer Cell, provides a solid framework for investigation of future targeted therapies that may improve the near uniformly fatal prognosis of this devastating cancer.
“Previous work has established that gene expression profiling can be used to identify distinct subgroups of GBM,” says senior study author, Dr. D. Neil Hayes from the Division of Hematology/Oncology at the University of North Carolina at Chapel Hill. “However, the exact number and clinical significance of these was unclear.” Dr. Hayes and colleagues at UNC Lineberger expanded on previous GBM classification studies and used expression profiling techniques to comprehensively analyze hundreds of GBM patient samples. The group was able to reliably identify four distinct molecular subtypes of GBM tumors.
The researchers then went on to perform a unique integrative analyses across multiple platforms to look for defining characteristics associated with each subtype. Their findings were quite striking, implying that there are distinct types of GBM and that each one is associated with a specific molecular process. “We discovered a bundle of events that unequivocally occur almost exclusively within a subtype,” explains Dr. Hayes.
The researchers also report that the nature of these events indicate that the underlying disease process for each subtype may involve distinct cells of origin at a specific stage of differentiation. This is finding has potential clinical significance as determining the cells of origin of GBM is critical for establishing effective treatment regimens. Clearly, given this new information, it makes sense that some drug classes would be expected to work for some tumor subtypes and not other. In support of this conclusion, Dr. Hayes’s group found that response to aggressive chemotherapy and radiation differed by subtype. Read more
No Change In Brain Tumor Incidence During A Time When Cell Phone Usage Increased
There was no substantial change in brain tumor incidence among adults 5 to 10 years after cell phone usage sharply increased, according to a new brief communication published online December 3 in the Journal of the National Cancer Institute.
Although cell phone use has been proposed as a risk factor for brain tumors, a biological mechanism to explain this association is not known.
Isabelle Deltour, Ph.D., of the Institute of Cancer Epidemiology, Danish Cancer Society, in Copenhagen, and colleagues analyzed annual incidence rates of glioma and meningioma among adults aged 20-79 years from Denmark, Finland, Norway, and Sweden. Researchers identified 60,000 patients who were diagnosed with these types of brain tumors between 1974 and 2003.
The researchers found that incidence rates over this 30 year-period were stable, decreased, or continued a gradual increase that started before the introduction of cell phones. They also found no change in incidence trends in brain tumors from 1998 to 2003. The authors say this finding may be due to one of several reasons: that the induction period relating cell phone use to brain tumors exceeds 5-10 years; that the increased risk in this population is too small to be observed; that the increased risk is restricted to subgroups of brain tumors or cell phone users; or that there is no increased risk. Read more
A Crystal Ball For Brain Cancer?
Bronnie McNabb, 57, considers himself lucky. When his aggressive brain cancer returned after chemotherapy and radiation last winter, his UCLA doctor prescribed the off-label use of Avastin, a drug shown to quell cancers in the breast, colon and lung.
One month later, McNabb’s tumors had shrunk by 95 percent. Subsequent brain scans show no trace of his cancer at all. The former marathon runner, ordained minister and father of two says he hasn’t felt this good since his diagnosis last winter.
In welcome news for patients like McNabb, the U.S. Food and Drug Administration approved the use of Avastin last month for the treatment of brain cancer. The powerful drug shrinks tumors by choking off their blood supply. Half of patients don’t respond to the therapy, though, exposing them to unnecessary side effects and medication costing up to $10,000 per month.
Now UCLA scientists have uncovered a new way to image tumors and forecast which patients, like McNabb, are most likely to benefit from Avastin before starting a single dose of treatment. The findings are published in this month’s issue of the journal Radiology. Read more