Researchers explain why men get more cancer
Kathryn E. Vinson, MS, CCRC
Cancer Is Sexist! – I recently stumbled upon an article from Harvard Magazine entitled “Why is Cancer More Common in Men?” This definitely sent my antennae up and I wanted to know more. The authors of this article tell us that while 1 in 3 women will develop some form of cancer in their lifetimes, 1 in 2 men will develop cancer. As an example, the American Cancer Society provides these estimated figures for diagnoses in 2017:
|Colon and Rectum||Lung and Bronchus|
This gender bias towards men was originally thought to stem from more exposure to carcinogens in the workplace, smoking, etc., but as women have become more equal to men in those statistics, the cancer rates have not changed. Pediatric oncologists even discuss higher rates of childhood cancers such as leukemia in boys over girls. With Father’s Day coming up this weekend, let’s take some time to understand why the men in our lives have this increased incidence.
Dr. Andrew Lane, of the Dana Farber Harvard Cancer Center, and his team of researchers have noted genetic differences between men and women that may account for these disparities.
If you think back to high school biology, you will recall that women have two X chromosomes, while men have an X and a Y. This may get you to thinking, well if there is a mutation on one X chromosome, women have the advantage because their other X chromosome could overpower that mutation, whereas men don’t have that advantage. Not so fast – in one of those miracles of our development, only one X chromosome is active in ladies, through a process called X inactivation.
Here is where it gets really tricky. Through some digging into the literature, Dr. Lane and his colleagues found that of the 800 genes on the X chromosome, about 50 escape inactivation – thus they continue to function while the others remain quiet. You guessed it – they realized that the gene mutations present in men with leukemia are in the region of those 50 genes that escape inactivation in women! They named these genes EXITS for “Escape from X-Inactivation Tumor Suppressors”. Simply put, when functioning normally, the EXITS help suppress tumor growth. In men, who only have one set on these tumor suppressors on their single X chromosome, a mutation in one or more of these genes can lead to tumor growth, whereas ladies have an extra set that may not have mutations, giving them extra protection. Further research showed that cancers other than leukemia presented with mutations in this region on the X chromosome.
So, other than the fact that men get more cancer than women, what does this mean? Well, it opens up a huge area of research in how men and women have been shown to have different physiological responses to treatments, as well as differences in the development of the same disease in the two genetic sexes.
It is important to remember that despite the fact that our genetics have a huge effect on our health, they are not the only factor in the development of certain cancers. As we know a whole host of factors come into play when we talk about cancer from environment to behaviors to diet, just to name a few.
As we talked about in Opening up About Prostate Cancer, only 3 in 5 men get regular physicals, and 19% report only going to the doctor to avoid getting nagged! Given this genetic pre-disposition, it is vitally important for men to get in there and have those physicals.
If a man in your life has cancer, check out our page dedicated to Gifts for Men to help brighten his day, or one of the many Support Groups and Cancer Associations for more information in fighting these diseases.