Kuo Lab Finds New Biomarker for Brain Cancer
Madison, Wisconsin - Glioblastoma multiforme (GBM) is both incurable and the most frequently diagnosed brain cancer in adults. But new research from the University of Wisconsin School of Medicine and Public Health lab of Dr. John Kuo, MD, PhD, shows that at least one subtype is associated with a longer life expectancy.
The discovery opens up new avenues of study for developing more effective therapies.
People diagnosed with GBM live on average less than two years after diagnosis, despite undergoing aggressive surgery, radiation and chemotherapy. But not all GBM cancers are the same, and Kuo's study outlines a new method for sub-typing GBM tumor lines by the proteins they express.
The July issue of the journal Clinical Cancer Research highlighted the research with a commentary by Dr. Jeremy Rich, of the Cleveland Clinic, who wrote that the UW study changes the current understanding of the cancer stem cells believed to drive this type of cancer.
The paper, published early online, shows that people who have a subtype of GBM that expresses a particular protein, known for short as CNP, survive longer with current therapies. The survival rate for those with the subtype is sometimes measured in years, not months.
The group isolated tumor lines from five human patients and grew them in the lab, and then looked for biomarkers specific to each line. They later transplanted the tissue into the brains of mice with compromised immune systems.
The researchers also looked for CNP expression in samples from 115 human patients and then looked at data on survival rates for those patients. They found that some patients with the protein lived much longer than the average survival after diagnosis.
"We found that this CNP expression was correlated with a less invasive cancer growths after implantation in mice brains, and when we looked at samples of human tumors, remarkably, we also found that the less invasive tumors expressed the CNP protein," says Kuo, assistant professor of neurological surgery and human oncology at the UW School of Medicine and Public Health.
Kuo, who directs the Comprehensive Brain Tumor Program for the UW Carbone Cancer Center, says the discovery opens new studies into cancer-cell migration, which contributes to the failure of modern therapies. Currently, most sub-typing of GBM tumors is based on mRNA, which can be difficult to do. But Kuo says that most hospitals can run assays for protein markers, so a CNP test is straightforward to move into clinical application.
In addition, says Michael Zorniak, Kuo's graduate student and lead author on the paper, the new way of sub-typing tumors could lead to better clinical choices of therapies for GBM patients.
"As we understand how tumors are differentiated, we can start devising and testing personalized therapies that are targeted to the specific GBM subtype," he says. "This can help us improve outcomes for brain cancer."
Date Published: 06/28/2012