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A Revealing New Study of Brain Tumors in the Prime of Life

Researchers at Case Western Reserve have completed the first-of-its-kind study of brain cancers that strike adolescents and young adults.

And they found a connection between the character of the tumors and the developmental stage of people diagnosed between the ages of 15 and 39.

These individuals "are in the reproductive prime of life and they have a different set of hormonally driven cancers than older adults," said Jill Barnholtz-Sloan, PhD, an associate professor at the School of Medicine, associate director of bioinformatics for the Case Comprehensive Cancer Center and senior author of the recent study.

The research was published earlier this year in the journal Neuro-Oncology.

Generally little focus and funding dollars have been directed to examining brain cancers in this population, said Elizabeth Wilson, president and chief executive officer of the American Brain Tumor Association, which commissioned the study and provided $80,000 for its completion.

"Here is a group of people at the peak of their careers," Wilson said. "They have young families. They're finishing school, and out of nowhere comes this diagnosis. We have an obligation to understand this group and the tumors they're dealing with."

Typically, funding has clustered around pediatric brain tumors or a deadly adult brain cancer (glioblastoma multiforme) more common after age 40.

Wilson said the recent study led by Barnholtz-Sloan is the first in-depth and comprehensive statistical analysis of brain and central nervous system tumors in adolescents and young adults and represents the first step in assigning new research priorities directed to the needs of this population.

"We wanted to ensure that researchers had as much data as possible for the adolescent and young adult group as is available for the other age groups," Wilson said.

Barnholtz-Sloan and her colleagues used data from the Central Brain Tumor Registry of the United States, teasing out the unique population characteristics of this group's brain cancers. The registry is an aggregate of data, covering 99.9 percent of the nation's population. Barnholtz-Sloan has been the registry's scientific principal investigator since 2012.

They found, for example, that a large proportion of brain tumors in the 15- to 39-year-old cohort are nonmalignant, compared with tumors in older adults and children. But even a non-malignant tumor in the brain nevertheless can be deadly due to the limited space and critical brain functions threatened by a slow-growing tumor.

The types of nonmalignant tumors also can be different, with the 15-39 group having a very high proportion of tumors of the pituitary gland.

This pea-size gland's vulnerability to tumors reflects its importance in the maturation of reproductive functions in this age group, Barnholtz-Sloan explained. Pre-cancerous gene mutations occur during cell division. The more divisions, the greater the risk of error, which makes developmental spurts vulnerable periods for the genesis of cancer.

The researchers also analyzed the data for the 15-39 group in five-year age increments, discovering that individuals are struck by very different tumor types as they move further into adulthood. "Our findings show this is not one group of individuals but rather distinct subgroups with different characteristics," Barnholtz-Sloan said. "There is a transition from predominantly non-malignant and low-grade tumors to high-grade tumors with increasing age."

—JENNI LAIDMAN