Featured Research

from universities, journals, and other organizations

One reason brain tumors are more common in men

Date:
August 1, 2014
Source:
Washington University in St. Louis
Summary:
New research helps explain why brain tumors occur more often in males and frequently are more harmful. For example, glioblastomas, the most common malignant brain tumors, are diagnosed twice as often in males, who suffer greater cognitive impairments than females and do not survive as long. The researchers found that retinoblastoma protein, a protein known to reduce cancer risk, is significantly less active in male brain cells than in female brain cells.

Reduced levels of an anti-cancer protein make male brain cells more vulnerable to becoming tumors, according to a new study at Washington University School of Medicine in St. Louis.
Credit: Robert Boston

New research at Washington University School of Medicine in St. Louis helps explain why brain tumors occur more often in males and frequently are more harmful than similar tumors in females. For example, glioblastomas, the most common malignant brain tumors, are diagnosed twice as often in males, who suffer greater cognitive impairments than females and do not survive as long.

Related Articles


The researchers found that retinoblastoma protein (RB), a protein known to reduce cancer risk, is significantly less active in male brain cells than in female brain cells.

The study appears Aug. 1 in The Journal of Clinical Investigation.

"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."

Rubin noted that RB is the target of drugs now being evaluated in clinical trials. Trial organizers hope the drugs trigger the protein's anti-tumor effects and help cancer patients survive longer.

"In clinical trials, we typically examine data from male and female patients together, and that could be masking positive or negative responses that are limited to one sex," said Rubin, who is an associate professor of pediatrics, neurology and anatomy and neurobiology. "At the very least, we should think about analyzing data for males and females separately in clinical trials."

Scientists have identified many sex-linked diseases that either occur at different rates in males and females or cause different symptoms based on sex. These distinctions often are linked to sex hormones, which create and maintain many but not all of the biological differences between the sexes.

However, Rubin and his colleagues knew that sex hormones could not account for the differences in brain tumor risk.

"Male brain tumor risk remains higher throughout life despite major age-linked shifts in sex hormone production in males and females," he said. "If the sex hormones were causing this effect, we'd see major changes in the relative rates of brain tumors in males and females at puberty. But they don't happen then or later in life when menopause changes female sex hormone production."

Rubin used a cell model of glioblastoma to prove it is easier to make male brain cells become tumors. After a series of genetic alterations and exposure to a growth factor, male brain cells became cancerous faster and more often than female brain cells.

In experiments designed to identify the reasons for the differences in the male and female cells, the team evaluated three genes to see if they were naturally less active in male brain cells. The genes they studied -- neurofibromin, p53 and RB -- normally suppress cell division and cell survival. They are mutated and disabled in many cancers.

The scientists found RB was more likely to be inactivated in male brain cells than in female brain cells. When they disabled the RB protein in female brain cells, 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 said. "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."


Story Source:

The above story is based on materials provided by Washington University in St. Louis. The original article was written by Michael C. Purdy. Note: Materials may be edited for content and length.


Journal Reference:

  1. Sun T, Warrington NM, Luo J, Brooks M, Dahiya S, Snyder SC, Sengupta R, Rubin JB. Sexually dimorphic RB inactivation underlies mesenchymal glioblastoma prevalence in males. The Journal of Clinical Investigation, Aug. 1, 2014

Cite This Page:

Washington University in St. Louis. "One reason brain tumors are more common in men." ScienceDaily. ScienceDaily, 1 August 2014. <www.sciencedaily.com/releases/2014/08/140801213341.htm>.
Washington University in St. Louis. (2014, August 1). One reason brain tumors are more common in men. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2014/08/140801213341.htm
Washington University in St. Louis. "One reason brain tumors are more common in men." ScienceDaily. www.sciencedaily.com/releases/2014/08/140801213341.htm (accessed October 24, 2014).

Share This



More Health & Medicine News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com
Ebola Fears Keep Guinea Hospitals Empty

Ebola Fears Keep Guinea Hospitals Empty

AP (Oct. 23, 2014) Fears of Ebola are keeping doctors and patients alike away from hospitals in the West African nation of Guinea. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Despite Rising Death Toll, Many Survive Ebola

Despite Rising Death Toll, Many Survive Ebola

AP (Oct. 23, 2014) The family of a Dallas nurse infected with Ebola in the US says doctors can no longer detect the virus in her. Despite the mounting death toll in West Africa, there are survivors there too. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Working Mother (Oct. 22, 2014) Is your child ready? Video provided by Working Mother
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins