Ecuadorean Dwarfs May Unlock Cancer Clues
A population of dwarfs is helping researchers find new drugs to prevent cancer.
Feb. 17, 2011 -- It's been more than two years since I traveled to Ecuador to meet endocrinologist Jaime Guevara, and the population of remarkable people who are helping scientists identify a way to stop cancer and diabetes from growing in our bodies. Dr. Guevara has been studying the Laron Dwarfs for 25 years, for the last decade he has been collaborating with Dr. Valter Longo, a researcher on aging at the University of Southern California. This week the two men released the findings of the research we chronicled in a series of reports on ABC News in 2008.
In Wednesday's issue of the journal "Science Translational Medicine" they revealed that the broken gene that causes dwarfism in a population of about 100 people in the remote mountains of Ecuador also offers them protection from cancer and diabetes. A 22 year study of the Larons has confirmed that none has ever had diabetes and only one had cancer and that cancer was not lethal. In contrast, the study looked at 1,600 normal-height relatives who live in the same towns and found that despite similar lifestyles 5 percent got diabetes and 17 percent got cancer.
As part of the research they mixed components from the Laron participants' blood with human cells from people not affected by the syndrome and found those components protect against cell damage and alter some genes that have been linked to life extension. When growth hormone was blocked in studies of mice they lived up to 40 per cent longer.
Surprisingly, Laron patients don't live longer than their taller relatives, Dr. Longo said. But many have emotional problems related to their Dwarfism and so the main causes of death are substance abuse and accidents.
Dr. Longo said drugs that block the growth hormone receptor in humans are already on the market for other purposes. In the next 12 months he hopes to start drug trials on a human population with a high propensity for cancer and diabetes. If the tests are successful, a pill to prevent cancer and diabetes could soon be as common as Lipitor and other statins are in the prevention of heart disease.
My left hand grabs the car seat, my right hand firmly clasps the handle above the passenger door inside our rented 4-by-4. We are bouncing our way up a deeply rutted road, passing banana trees and grazing donkeys.
This is remote, rural southern Ecuador. A tropical Appalachia that until recently was cut off from the rest of the world. It seems the most unlikely of places to go in search of the cause of cancer, and maybe a cure.
Behind the wheel of the 4-by-4 is Dr. Jaime Guevara, an endocrinologist from Quito, Ecuador's capital. Almost 25 years ago, he began studying a scattered group of dwarfs in this area who have a rare disorder called Laron dwarfism, or Laron syndrome, that stunts their growth. In medical terms, their growth hormone receptors are blocked.
"There are only about 300 patients, and there are about 100 in Ecuador," says Guevara as he navigates the twisting road. "So in Ecuador you can find about one-third of the world's population with this disorder."
We stop at a modest cinder block building perched on a hillside. There is no glass in the windows, nothing but a few plastic chairs inside. We are welcomed into the home of Narcisa Lois and her three children. Her husband, a farm laborer who supports the family on a few dollars a day, is away at work.
Guevara is quick to point out that the smallest of the children is not the youngest. Five-year-old Yoneli stands less than 2 feet tall, 4 inches shorter than her sister. Yoneli has Laron syndrome.
The rest of the family is of normal height. Yoneli's mother had no idea that both she and her husband carried the recessive gene that randomly surfaces to cause Laron Syndrome.
"The condition needs to have the father and mother who have the mutation," explains Guevara. It is passed on through inbreeding, which is very common in this remote tropical Appalachia. There is no mystery here: Narcisa and her husband are first cousins. "Isolation, that's the whole thing," says Guevara.
Twenty years ago, when Guevara began treating and studying the dwarfs of southern Ecuador, it was because he wanted to help them. But an interesting and quirky pattern started to emerge. He realized that there has never been a single incidence of cancer or diabetes among them.
"I start noticing that somehow in this area that we all know in Ecuador is an area with high rates of cancer, not one of these patients has ever died of cancer," he says. "And I'm talking about a total of 135 names that I can think of. None of them has ever died of cancer. To me the possibility that that is a coincidence is almost none, because every single family in this case has at least one or two or three relatives that have died of cancer."