Fri, Aug 18, 2017 | updated 05:17 AM IST

Study reveals why men more prone to cancer than women

Updated: Nov 23, 2016 16:49 IST      
Study reveals why men more prone to cancer than women

Washington D.C. [USA], Nov. 23 (ANI): A recent study published online by Nature Genetics reveals as to why male are more prone to cancer than their female counterparts.

A group of Boston scientists, including researchers at Dana-Farber Cancer Institute, offer a genetic explanation for the age-old conundrum of why cancer is more common in males than females.

Females, it turns out, carry an extra copy of certain protective genes in their cells -- an additional line of defense against the cells growing out of control -- the investigators report.

Though not solely responsible for cancer's "bias" toward males, the duplicate copies likely account for some of the imbalance, including up to 80 percent of the excess male cases in some tumor types, report the study authors based at Dana-Farber, the Broad Institute of Harvard and MIT, and Massachusetts General Hospital.

"Across virtually every type of cancer, occurrence rates are higher in males than in females. In some cases, the difference might be very small -- just a few percent -- but in certain cancers, incidence is two or three times higher in males," said Andrew Lane, MD, PhD, of Dana-Farber, the co-senior author of the study with Gad Getz, PhD, of the Broad Institute and Massachusetts General Hospital.

"Data from the National Cancer Institute show that males carry about a 20 percent higher risk than females of developing cancer. That translates into 150,000 additional new cases of cancer in men every year," Lane added.

Despite the gap size, the reasons for this divergence have been difficult to discern. The historic explanation -- that men were more likely to smoke cigarettes and be exposed to hazardous chemicals in the work environment -- has proven inadequate because even as smoking rates have dropped and occupational patterns changed, men still outpace women in developing many cancers including some associated with tobacco use such as kidney, renal, bladder and oral cancers, Lane said.

The disparity is present among boys and girls as well as men and women.

Previous research found that in one form of leukemia, the cancer cells often carried a mutation in a gene called KDM6A, located on the X chromosome -- one of the sex chromosomes that determine whether an individual is male or female.

(Females cells carry two X chromosomes; males carry an X chromosome and a shorter, smaller Y chromosome.) If KDM6A is a tumor-suppressor gene -- responsible for preventing cell division from spinning out of control -- the mutation could lead to cancer by crippling that restraint system.

One might expect female cells to be just as vulnerable to the mutation. During embryo formation, one of the X chromosomes in female cells shuts down and remains off-line for life. A mutation in KDM6A on the active X chromosome, therefore, should lead to the same cell-division havoc as it does in males.

Unexpectedly, KDM6A mutations were detected more often in male cancers. It turns out that some genes on the inactivated X chromosome in female cells "escape" that dormant state and function normally. One of those awakened genes happens to be a working copy of KDM6A. The "good" copy of the gene is sufficient to prevent the cell from turning cancerous.

The new study explored whether this phenomenon -- fully functional tumor-suppressor genes on an otherwise idle X chromosome -- underlies the broader phenomenon of cancer's partiality toward male cells.

The researchers dubbed such genes "EXITS," for Escape from X-Inactivation Tumor Suppressors.

"Under this theory, one of the reasons cancer is more common in males is that male cells would need a harmful mutation in only one copy of an EXITS gene to turn cancerous," Lane said.

"Female cells, by contrast, would need mutations in both copies."

To test this hypothesis, researchers at the Broad Institute scanned the genomes of more than 4,000 tumor samples, representing 21 different types of cancer, looking for various types of abnormalities, including mutations. They then examined whether any of the irregularities they found were more common in male cells or female cells.

The results were striking. Of nearly 800 genes found solely on the X chromosome, six were more frequently mutated -- and incapacitated -- in males than females. Of more than 18,000 other genes, none showed a gender imbalance in mutation rates.

Of the six genes more likely to be mutated in males, five were known to escape X chromosome inactivation, making them strong candidates to be EXITS genes.

"The fact that the very genes which are more often mutated in males are found exclusively on the X chromosome -- and that several of them are known to be tumor-suppressors and escape X-inactivation -- is compelling evidence of our theory," Lane remarked.

"The protection afforded by the working copies of these genes in female cells may help explain the lower incidence of many cancers in women and girls," he added.

One of the implications of the finding is that many cancers may arise through different molecular pathways in men and women. To circumvent the added genetic safeguards against cancer in fe male cells, tumors in women may employ alternate genetic circuits than in men.

To explore this possibility, the study authors recommend that future clinical studies of cancer treatments be "statistically powered" ¬- that is, involve enough patients and tumor tissue samples -- to understand whether men and women respond differently to treatment because of genetic differences in their tumors. (ANI)

Japan introduces solar heat-blocking pavements

Updated: Aug 17, 2017 14:10 IST     

Tokyo [Japan], Aug.16 (ANI): The host city of Olympic and Paralympic Games in 2020, Tokyo is working on heat blocking methods during the summer.

Full Story >>

New Delhi [India], August 17 (ANI): The Fortis Foundation recently launched two charitable medical dispensaries at the Anubhavi Ashram in Haridwar, Uttarakhand and at the Aggarwal Dharamshala in New Delhi.

Full Story >>

Nagpur (Maharashtra) [India], Aug.15 (ANI): The public sector Oil and Natural Gas Coroporation (ONGC) has extended a support of Rs 100 crore to turn the vision of affordable world class cancer care facilities in Central India into reality.

Full Story >>

Are tidally-locked exoplanets more common than believed?

Updated: Aug 15, 2017 10:16 IST     

Washington D.C. [USA], Aug 15 (ANI): There's a possibility for a lot more exoplanets to be tidally locked, according to new research.

Full Story >>

Robots lend a helping hand to esophageal surgeons

Updated: Aug 13, 2017 05:25 IST     

Washington D.C. [USA], Aug 13 (ANI): Robots are no longer just useful tools to make life easy and convenient; turns out, some of them can offer key advantages in esophageal surgeries.

Full Story >>

Are USB connections putting your data at risk?

Updated: Aug 11, 2017 04:21 IST     

Washington D.C. [USA], Aug 11 (ANI): Turns out, USB connections, the most common interface used globally to connect external devices to computers, make snooping easy.

Full Story >>

Turns out, you can catch 'Science' bug from peers

Updated: Aug 10, 2017 07:17 IST     

Washington D.C. [USA], Aug 10 (ANI): According to a recent study, developing an interest in Science as is simple as sitting next to a bunch of students fascinated by the topic.

Full Story >>

Washington D.C. [USA], Aug 9 (ANI): During a walk near a reservoir in a small Japanese town, amateur collectors made the discovery of their lives - the first and oldest fossil bird ever identified in their country.

Full Story >>

Ocean's fastest shark at risk of being 'overfished'

Updated: Aug 09, 2017 01:46 IST     

Washington D.C. [USA], Aug 9 (ANI): Overfishing is putting the ocean's fastest shark at risk, according to a recent research.

Full Story >>

20-month-olds can understand difference between two languages

Updated: Aug 08, 2017 07:12 IST     

Washington D.C. [USA], Aug 8 (ANI): Are two languages at a time too much for the infant mind? According to a recent study, babies as young as 20 months can understand a lot more than you'd think.

Full Story >>

Washington D.C. [USA], August 7 (ANI): Researchers have developed a learning method to change cognitive function by manipulating connections in the brain.

Full Story >>

Kicking butts to the curb

Updated: Aug 07, 2017 00:57 IST     

Washington D.C. [USA], Aug 7 (ANI): Cigarette butts are more than mere litter and now, a team of scientists has found a way to pave over the big problem.

Full Story >>

Desert tortoises can't take heat of roadside fencing

Updated: Aug 06, 2017 13:55 IST     

Washington D.C. [USA], August 6 (ANI): US researchers have revealed that roadside fencing, which is meant to help desert tortoise, can actually overheat them leading to their death.

Full Story >>

Scientists unveil how brain works with the help of magic

Updated: Aug 02, 2017 14:58 IST     

Washington D.C. [USA], August 2 (ANI): To tap into brain's 'out-of-the box' thinking, scientists are now relying on magic tricks and illusions.

Full Story >>

Climate change could put rare bat species at greater risk

Updated: Aug 02, 2017 13:52 IST     

New Delhi [India], Aug 02 (ANI): An endangered bat species with a UK population of less than 1,000 could be further threatened by the effects of global warming, according to a new study led by the University of Southampton.

Full Story >>

London [UK], July 31 (ANI): If you are tired of trying every means to fight obesity, then this new discovery might help you to rethink.

Full Story >>

Climate change may cause more rain, nitrogen runoff

Updated: Jul 29, 2017 11:36 IST     

Washington D.C. [USA], July 29 (ANI): An intensifying water cycle will likely cause dramatic increases - nearing 20 percent by 2100 - in the amount of nitrogen runoff in the U.S., according to a new study.

Full Story >>

Washington D.C. [USA], Jul 27 (ANI): A recent atomic discovery has paved the way for greener, faster, smaller electronic circuitry.

Full Story >>

New Delhi [India], July 24 (ANI): Toronto Recombinant Antibody Centre (TRAC) from the University of Toronto, Canada agreed to license MedGenome's patented cancer immunotherapy solution OncoPept to develop biomarkers for their drug candidates against immune modulators to treat cancer.

Full Story >>

Spitting out clues to 'ghost species' of ancient human

Updated: Jul 23, 2017 13:15 IST     

Washington D.C. [USA], Jul 23 (ANI): Ancient Africans may have engaged in a 'sexual rendezvous' with a 'ghost' species of archaic humans, according to a recent study.

Full Story >>