Cindy Solomon chuckles while she watches 8-year-old Ella pour a packet of sugar into her own mouth, stimulating her salivary glands to produce a "spit sample" for testing at Huntsman Cancer Institute.
For Ella, the sugar is a rare treat. For her health-conscious mom, it's a nutritional sacrifice for science.
The Solomons are among 1,000 mother-and-daughter duos from the United States and Canada taking part in a long-term study of environmental, dietary and family links to breast cancer.
Funded by the U.S. National Institutes for Health, the "Legacy" study represents a shift in the focus of cancer research from diagnosis and treatment to prevention. And it's one of the few involving girls so young, between ages 6 and 13.
Ella has no significant family history of cancer. Her mom heard about the study through a neighbor.
"We talked about how it would help scientists better understand cancer," said Cindy, who told Ella that even though she's not at risk, "You know people who have had the disease, and if you can help scientists and it's fun, why not do it?"
Traditionally, researchers have focused on older women, asking them to recall details about their lives that may have predisposed them to breast cancer, said Saundra Buys, a principal investigator and co-director of the High Risk Breast Clinic at Huntsman.
"But more and more younger women are being diagnosed," said Buys.
And increasingly, risk factors are being traced back to our early years, she said.
Legacy -- an acronym for Lessons in Epidemiology and Genetics of Adult Cancer from Youth -- is being done at Breast Cancer Registry sites in San Francisco, New York, Philadelphia, Toronto and Salt Lake.
The Solomons are among 150 enrolled through Huntsman.
Every six months for at least five years they will answer detailed questionnaires about their exercise habits, the food they eat and the cosmetics, hair gels and perfumes they use.
Ella will be measured and weighed and will volunteer saliva and urine for testing hormonal and genetic changes.
She also agreed to give blood -- it's optional -- which didn't seem to bother the wiggly, giggly girl at her last clinic appointment in August.
Clinic visits are kept upbeat. Many of the participants have lost close relatives, such as an aunt, grandmother or older sibling, but none of the girls will be tested for the breast cancer genes, BRCA1 or BRCA2.
"A lot of them had a mom who died of breast cancer and they're coming in with their dad. That's why there was a lot of talk up front about how to frame this," said Buys.
After Ella's visit, she got to pick a plush toy to take home. The girls also get snacks and gift certificates. Adorning the clinic's walls are photos of puppies, kittens and teen heartthrobs like Justin Bieber.
"My daughter knows what cancer is, but I don't think she associates the study with cancer. They don't talk about cancer or dying. It's more like, ‘What are you girls doing to keep your bodies healthy?' " said a 32-year-old study participant whose mother died six months ago from cancer.
She asked to be kept anonymous to protect her 10-year-old daughter against prejudice from employers and insurers. "My mother didn't find out she had the genetic mutation until after she was diagnosed with stage 4 ovarian cancer. She also had breast cancer at a young age, in her 30s," said the Salt Lake County woman. "It's definitely something I'm concerned about for me, my daughter and her children.
"I would rather not sit and wait and wonder, but be as proactive as I can. If finding better detection and prevention options means schlepping my daughter and her friends up to Huntsman, so be it," she added.
By comparing girls from shared environments, researchers hope to better understand why some get cancer and others don't.
They'd like to follow the girls for 10 years or more, though the study is currently only funded for five -- not long enough to see if any of the girls develop cancer.
"We can't look at breast cancer outcomes," said Esther John, another principal investigator who works at the Cancer Prevention Institute of California. But the group can learn how lifestyle and environmental exposures trigger changes in the girls' bodies that make them more prone to breast cancer, she said.
John is interested in examining how exercise and body size effect puberty. Girls in the U.S. are hitting puberty at younger ages, prolonging the exposure of their developing breasts to hormones that raise their cancer risk.
Researchers will also look at hormones such as insulin and melatonin, thought to reduce the risks of some cancers.
The team in Toronto will be using optical spectroscopy to shine a light into the girls' breast tissue to measure fatty tissue and oxygenated blood, said Buys. It's a way to divine breast density, another risk factor, without exposing the girls to radiation, she said.
"We could ask, are these girls the ones who are most likely to be consuming a lot of foods in plastic containers, or to be exposed to endocrine disrupters in the form of hair sprays?" she said.
Other teams will delve into behavioral factors, asking how families talk and think about breast cancer. How do they cope with stress? Do they live in walkable communities with easy access to grocery stores and healthy food?
There's no disputing that cancer has a strong genetic component. But a large majority of breast cancer cases happen in women with no family history of the disease.
Worldwide it is the most commonly diagnosed malignancy and the leading cause of cancer death among women. In 2012, an estimated 229,000 Americans will be diagnosed with breast cancer and 40,000 will die from it, according to the Interagency Breast Cancer and Environmental Research Coordinating Committee.
Yet only about 10 percent of government-funded research has focused on environmental causes, according to a 2013 report by IBCERCC, which calls for a different approach.
"How we do research matters," said Jeanne Rizzo, IBCERCC co-chairwoman and president of the national advocacy group, the Breast Cancer Fund. "We need to study people in real-life scenarios, multiple exposures over time and not just ask, ‘Are we 95 percent sure that this one chemical caused this one disease in most people who were exposed to it?'"
The value of studies like Legacy, said Rizzo, is the broad sweep of data collected.
"When you go to the doctor, they may ask if you smoke or drink alcohol, but they don't ask anything about workplace exposures or what chemicals you use," she said. "So when we turn around and try to understand how a person gets sick, we don't have the data."