An NCI-designated Comprehensive Cancer Center
By Samantha Bonar | February 28, 2018
Rick Kittles Rick Kittles, Ph.D.
For Rick Kittles, Ph.D., founding director of the Division of Health Equities within City of Hope's Department of Population Sciences, exploring genes and environments to understand health disparities among different populations isn’t just a scientific pursuit — it is a passion driven by social justice concerns.
Spurred by his grandfather’s death from prostate cancer while he was in graduate school, for more than 20 years Kittles has dedicated his life to teasing out which health disparities have a genetic basis and which are environmental or behavioral in origin.
His work has shown the impact of genetic variation across populations in pharmacogenomics, biomarker discovery and disease gene mapping. His research is in pursuit of a relatively new term: health equity.
Health equity explores ways in which we can engage and intervene to eliminate some of those differences that we see across populations,” Kittles explained.
“For example, black women are much more susceptible to triple-negative breast cancer. Asians are diagnosed with stomach cancer at a much higher rate. It’s very clear that across many cancers there are various inequities in incidence and outcomes, and we’re looking at ways that we can level that playing field.”
Although a major focus of Kittles’s work has been measuring West African admixture in studies of genetic disease — particularly prostate cancer — among African-Americans, he is currently expanding his research focus to include Latino and Native American populations. The bulk of his disease research is in cancer genetics (including prostate, colon and breast), but Kittles also is involved in research into other complex diseases such as sarcoidosis, lung and cardiovascular disease, and sickle cell disease.

Biology vs. Behavior

“We know that when we look across populations — these different socioeconomic, demographic groups — we see these differences in incidence and mortality and outcomes in disease,” he said.
The question is, is that due to biological differences or behavioral differences? One way we can determine if biology is playing a role is if we look at genetic ancestry to find if there is an ancestral component to the risk. If there isn’t one, then it’s more likely social behavior.”
Head and neck cancers, for example, display a strong disparity in outcomes among different populations. However, “We don’t see ancestry being associated with those outcomes,” said Kittles, who received a Ph.D. in biological sciences from George Washington University in 1998. “The biggest predictor of outcome is insurance status.” For other diseases, such as prostate cancer, “We see a very strong ancestry effect. For black men, the incidence is 1.8 percent higher. It’s a lot more aggressive and genetically driven in blacks than it is in whites,” Kittles said, especially among black men with more West African ancestry.
“We don’t see that for head and neck cancer, we don’t see that for sporadic breast cancer and we don’t see that for colorectal cancer,” Kittles said. “It’s mainly social and behavioral differences that contribute to those disparities.”
In diabetes, too, studies do not show a significant genetic component: “That is one of those disparities that has a very strong behavioral component to it,” Kittles said.

Identifying and Addressing Risk

The goal of Kittles’s research is to develop a more tailored approach to screening and treatment, and one that is more equitable based on these differences across populations. “What this approach does is it allows us to risk stratify,” he explained. “It allows us to identify individuals who need increased screening.” For prostate cancer, for example, rather than just using PSA levels, ancestry should be added as a component of risk, Kittles said.
Another way genetic screening is useful for addressing health disparities is in the area of pharmacology. “There are certain drugs where the response to the drug differs according to the ancestry,” Kittles said. For example, people respond to the blood thinner Warfarin differently according to their genetic and ancestral profile. “If you are prescribed Warfarin, they will do a blood test that looks for alleles to help set the dosage. This is routine now,” Kittles said.
Someday, Kittles said, your genetic profile “will be part of your medical record so that your physician can use it for everything from risk assessment to drug selection based on your known genotypes.” This highly individualized approach is called precision medicine.
The problem, though, is that such genetic profiling is expensive, Kittles said. Disadvantaged communities “don’t have access to these tests or doctors who understand these tests. There has to be equity across populations, or it will just increase disparities. The science is there, but not the equitable components.
“Precision-medicine disparity is a social justice issue,” he continued. “We will continue to see the gap widen as we roll out precision medicine. But I’m very passionate about this. I advocate for equitable benefits, and part of getting there is educating the community and getting them excited, involved in the research and ultimately to lobby for their communities [to get genetic testing]."

Educating the Community

Part of the excitement for Kittles in being at City of Hope, which he joined last May from the University of Arizona, “is to go out and educate folks about what is going on,” he said. “We are at a very interesting point in terms of precision medicine, understanding genetic ancestry and risk stratification. I’m going to go out and educate the community in order to get them excited and get them to participate in this effort. There are isolated communities, places where people aren’t being touched by health care the way they should be. Those are the places I have a strong passion and interest in.”
He pointed out that City of Hope has more than 15 community clinic sites across three counties. “There’s opportunity for City of Hope to be quite impactful in terms of disparity research and interventions,” he said. “But the community has to buy into it.”
Through education, advocacy and participation, “ultimately, we will provide more efficient health care because of that process,” Kittles said. “It’s more than just providing a [genetic] database, it’s about providing accessibility and opportunity for physicians to utilize the science and technology in better and more equitable ways. The sad part about this is that not only is it costly, the cost is creating a disparity not just in outcomes, but in information also. The bulk of the information that we have is on whites. The people who are benefiting from that technology now are white.”
However, Kittles believes strongly that “we can change the game. You just need to have dedicated folk go out and do it and do it in a way that impacts policy and utilization.”

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