Research explains Why deadly Brain Tumors are More Common Among Men

A protein that reduces brain cancer risk is less active in men than in women, a new study has found.

According to the researchers at the Washington University School of Medicine in St. Louis, the study might help explain why men suffer from a high risk of brain tumors such as glioblastomas.

Glioblastomas (GBM) are tumors that affect the astrocytes, which are star-shaped cells that support the brain cells. GBMs are highly malignant and spread quickly in the brain.

The team found that retinoblastoma protein (RB) is less active in male brain cells than female brain cells.

"This is the first time anyone ever has identified a sex-linked difference that affects tumor risk and is intrinsic to cells, and that's very exciting," said senior author Joshua Rubin, MD, PhD. "These results suggest we need to go back and look at multiple pathways linked to cancer, checking for sex differences. Sex-based distinctions at the level of the cell may not only influence cancer risk but also the effectiveness of treatments."

The RB protein is currently the target for drugs designed to treat brain tumors, Rubin said.

For the study, researchers used a cell model of brain tumor. They demonstrated that it is far more easy to make male brain cells cancerous than female brain cells. The team used genetic alterations and growth factors to show how male brain cells can become tumors.

To understand the genetic basis of the difference between male and female tumor development, researchers focused on three genes - neurofibromin, p53 and RB. These genes are known to play an important role in cell division and survival. Other research has shown that these genes are suppressed in several cancers.

The team found that RB was more likely to be involved in tumor development than other genes. When researchers suppressed RB in female brain cells, they found that the cells were as likely to form tumors as male brain cells.

"There are other types of tumors that occur at different rates based on sex, such as some liver cancers, which occur more often in males," Rubin said in a news release. "Knowing more about why cancer rates differ between males and females will help us understand basic mechanisms in cancer, seek more effective therapies and perform more informative clinical trials."