Research on Twins Leads to New Cancer Treatment

Who hasn’t secretly wished for a double? You could send them to do your dirty work, try out new haircuts on them, or be two places at once. No one would know the difference. Mary Kate and Ashley Olsen fooled audiences into thinking they were a singular, hackneyed Michelle Tanner for years. As the decades and tabloids have revealed, they are in fact different people, though not by much.

Being womb-mates does not ensure identical talents, taste in music, or sense of humor. But what’s more interesting is that the differences between identical twins transcend past personality into biology. If two people are genetically identical, why will one get breast cancer while the other does not? Why will one go gray in his thirties, but the other looks young well into his forties?

As usual, scientists went to the microscope to look for an answer.

In every type of human cell—liver, skin, neuron, you name it—the same DNA exists inside the nucleus. However, the cell’s “epigenomes” make cells different from each other. These molecules silence certain genes, allowing others to be expressed. They give the cell a little direction in life. Think college career counselor, at the molecular level: "you would be great for the digestive system." Contrary to DNA, which is duplicated exactly every time a cell divides, researchers believe epigenomes can change according to the cell’s environment. The Nature adapts to the Nurture.

Sure enough, as identical twins age, their epigenomes get more and more different from each other, according to research conducted by Manel Esteller at the Spanish National Cancer Center in Madrid. These changes are influenced by the stuff we eat, drink, and breathe (i.e. cigarettes). If something environmental screws up a cell’s epigenetics, crucial genes can be silenced accidentally, and the cell goes haywire (i.e. lung cancer). Imagine if your college career counselor emailed you about an opening at Barnum & Bailey for a lion tamer, instead of ::insert perfect-job-with-benefits here:: It’s kind of like that.

Luckily, the new findings on epigenomes in twins have helped develop therapies for these mis-advised cells—typically in cancers. Doctors are trying to correct the epigenomes of the cancerous cells in order to make them normal again, rather than just killing them off with chemo. Time will tell how well their diplomatic approach works in the long run, but so far the results seem promising.

Image Credit: Flickr user Stoneth