Sen. John McCain’s glioblastoma diagnosis is bleak, but not hopeless, according to Dr. Eyas Hattab, Chair of the College of American Pathologists Neuropathology Committee.  Personalized medicine holds the key to the tests that pathologists will be conducting this week and beyond. The two groups of glioblastoma tumors appear identical under the microscope, but genetics determine a patient’s course of treatment. 

“Personalized medicine today allows for the classification of glioblastomas into two main categories based on their genetic makeup,” Dr. Hattab said. “About 90 percent of glioblastomas are “bad actors”, usually with survival periods under 1 year while the remainder may live for about 5 years or longer. In addition to rendering the diagnosis of glioblastoma, the role of the pathologist is to determine to which genetic group a patient belongs. 

While these tumors appear identical under the microscope, a tumor’s response to therapy differs from one patient to another depending on certain molecular characteristics. Through molecular testing, the laboratory is able to predict which tumors will respond better to certain chemotherapeutic and radiation therapies.”