Driver mutation

What it is

A driver mutation is a genetic change that actively promotes the development and growth of a tumor — as opposed to "passenger" mutations, which are present but do not drive the cancer. Identifying a glioma's driver mutation can reveal both its biology and potential treatment targets.

Understanding Driver mutation

Tumors accumulate many genetic changes, but only some actively cause and sustain the cancer; these are the drivers. In gliomas, key driver mutations include IDH mutations (in adult diffuse gliomas), BRAF changes (in many pediatric low-grade gliomas), and H3 mutations (in pediatric high-grade gliomas). Understanding the driver helps classify the tumor and, importantly, can point to targeted treatments — for example, a BRAF V600E driver can be treated with BRAF inhibitors, and an IDH driver with IDH inhibitors. Distinguishing drivers from passengers is a central goal of molecular testing. Understanding driver mutations clarifies the genetic changes that actively fuel a glioma and often serve as treatment targets.

Why it matters

Understanding driver mutations helps patients and families see why identifying the change that fuels the tumor matters — it clarifies the diagnosis and can reveal a targeted treatment aimed directly at the tumor's driver.