The discovery of the telltale molecular signature ?the expression of a mutant protein and the presence of a tumor suppressor protein called PTEN ?will allow researchers to identify patients who are likely to respond to the drug treatment before they undergo therapies that are not likely to work, said Dr. Paul Mischel, an associate professor of pathology and laboratory medicine and a Jonsson Cancer Center researcher.
Mischel and his colleagues say in an article in the Nov. 10 issue of the New England Journal of Medicine that the discovery could change the way doctors treat glioblastomas, the most common type of malignant brain tumor and one of the those lethal forms of cancer.
"In a biologically aggressive disease like glioblastoma, it's vital to be able to stratify patients up front so we can treat them with drugs that they are more likely to respond to," Mischel said. "This will help prevent patients from having therapies that are much more toxic and less beneficial. With the short survival times associated with glioblastoma, that is critical."
Between 8,000 and 10,000 new cases of glioblastoma will be diagnosed in Americans this year. Average survival is less than a year, according to the American Cancer Society. Although treatment may prolong life, most malignant brain tumors are not curable, making the search for better treatments even more urgent, Mischel said.
A protein called epidermal growth factor receptor (EGFR) is commonly amplified in glioblastoma, making it a prime focus for therapies. Drugs such as Tarceva and Iressa target EGFR, blocking the cell signals that drive amplification of the protein and speed cancer growth. A subset of glioblastoma patients responded to Tarceva and Iress
Source:University of California - Los Angeles