Scientists are observing 100 people from a remote village in Ecuador, as only one of those people has died from cancer in the past 30 years.
What makes this group particularly unusual is that they all suffer from Laron Syndrome, a rare disorder which results in the body's inability to grow. Those who are affected experience slow growth from early childhood.
Researchers - led by Dr Jaime Guevara-Aguirre, who has been studying the Laron population for 30 years - believe the genetic makeup of these people could hold the key to preventing major illnesses such as cancer and diabetes.
They hope to harness the anti-disease properties of Laron Syndrome to create a special pill.
If left untreated, adult males with Laron Syndrome typically grow to around 4.5 feet, meanwhile women can reach up to 4 feet.
One of the villagers being observed in the study, Merci Valarezo, 50, is just 3ft 6" and weighs 127 pounds (just over nine stone).
This puts her firmly in the morbidly obese category, however scientists say that she is "healthy". Her diet is high in carbohydrates and fats but her blood pressure is perfect. She has no sign of diabetes or any other illnesses.
Researchers believe that people with Laron Syndrome have a defect in their growth hormone receptor. This receptor is meant to bind the growth hormone and produce a substance called insulin-like growth factor 1 (IGF-1).
However because the binding doesn't happen in patients with Laron Syndrome, there is no IGF-1.
It can also make the body extra sensitive to insulin, which may protect against diabetes.
In a study of rats, Dr Longo found that animals with Laron Syndrome lived 50% longer and developed fewer diseases. He now hopes to replicate this finding into a pill which would block IGF-1 in humans.
However he did add that researchers wouldn't know whether the pill worked or not for at least 10 years.
"Prevention offers the most cost-effective long-term strategy for the control of cancer," WHO adds.
Quitting smoking, exercising, eating healthily and cutting down on alcohol consumption are all advised.