Molecular biology of brain tumors impact prognosis, treatment

Understanding the molecular biology of brain tumors is key to prognosis and treatment, said Le Bonheur Neuroscience Institute Co-Director Frederick Boop, MD, in his presentation “How Molecular Biology Impacts Clinical Practice” at the International Society for Pediatric Neurosurgery (ISPN) 2020 Virtual Meeting.

“Historically we have depended on what we see under a microscope to differentiate tumor types and determine prognosis and therapy,” said Boop. “We know now that what we see doesn’t necessarily predict how these tumors are going to behave.”

Physicians are able to send a piece of a child’s tumor to FoundationOne, an FDA-approved tissue-based broad companion diagnostic (CDx) for solid tumors, which provides the genomic alterations of that particular tumor. This explanation of the genetic aberrations includes its significance, best available treatment with mechanism of action and studies open for enrollment.

Manipulation of tumors based on molecular genetics began more than 35 years ago with shrinking prolactinomas before turning to neurosurgery. Boop and his team now use a molecular biological approach with medulloblastomas, lowgrade gliomas, congenital glioblastomas and many more types of brain tumors. Closer study of molecular genetics has revealed different variants within each type of tumor, each with a different treatment approach and prognosis based on the genetic variant. Further study is needed into treatment side effects and long-term consequences for some of these therapies.

“As neurosurgeons, it is important for us to get tissue to the lab in every instance for us to understand what’s going on so that these children can have a chance,” said Boop.

For tumors that can’t be removed surgically but tissue is needed for diagnostics, biopsies provide better understanding and treatment of the tumor. Previously, neurosurgeons avoided these biopsies because it was believed that the cells required were closest to necrotic areas that could cause catastrophic complications. Better understanding of tumors means that the tumor can be biopsied in a safer area in order to obtain the molecular profile of the tumor.

“Molecular genetics has completely changed our field and will continue to do so,” said Boop. “There may come a time when the role for surgeons is much less than it is today.”