Some Brain Tumors are More Common in Men: Cancer-Fighting Protein Found in Females Explains Why

Many medical conditions favor one sex over the other. As brain tumors remain the second leading cause of cancer-related deaths among children under 20 and males between the ages of 20 to 39, this health issue is more likely to present in male patients than female ones. 

A recent study conducted by researchers at Washington University in St. Louis, Mo., examines why some brain tumors are predominantly more common in men. By looking at glioblastomas, or the most common malignant brain tumors that are diagnosed twice as often in males as females, researchers found that the retinoblastoma protein (RB), a protein that helps to reduce cancer risk, is also significantly less active in male 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, in a news release. "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."

Researchers also noted that RB, the target of many drugs, is currently being evaluated in many clinical trials. Organizers have stated that the drug works to trigger the protein's anti-tumor effects, which can help cancer patients survive longer.

Study findings also revealed that RB is more likely to be inactivated in male brain cells than female ones. Throughout their research, the study authors worked to disable the RB protein found in female brain cells. As this occurred, they found that the cells were equally susceptible to becoming cancers.

"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 added. "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."

More information regarding the findings can be seen via the Journal of Clinical Investigation.