UH Cancer Center researchers study factors of racial/ethnic disparities

March 18 2021

The National Cancer Institute’s (NCI) Epidemiology and Genomics Research Program (EGRP) announced the selection of 36 publications as research highlights from EGRP-funded cancer epidemiology studies of 2020. Two of these publications used data from the University of Hawaiʻi Cancer Center’s Multiethnic Cohort (MEC) Study, a large epidemiological study that follows residents of Hawaiʻi and Los Angeles for the development of cancer and other chronic diseases.

In one publication led by the UH Cancer Center’s Loïc Le Marchand, MD, PhD, researchers demonstrated that intra-abdominal fat, also known as visceral adipose tissue (VAT), could be predicted using common biochemical markers in blood, and that the predicted VAT was associated with cancer risk. They found that women with a high VAT score in the MEC Study were at greater risk for developing breast cancer, even at comparable levels of body weight or total body fatness.

VAT is known to have more harmful metabolic effects than the fat found underneath the skin. The investigators had reported earlier that VAT amounts vary substantially by race/ethnicity at a given body weight, which may explain obesity-related cancer disparities. “Since accurate VAT measurement requires expensive imaging tests, the assessment of VAT based on easily measurable biomarkers, like those found in blood, is important for future studies of obesity-associated cancer and other diseases,” said Le Marchand.

The second publication , from another NCI grant led by Unhee Lim, PhD, at the UH Cancer Center, studied the gut bacteria of MEC Study participants in relation to their levels of a blood marker, trimethylamine N-oxide (TMAO), that is known to be elevated in people who consume more animal products or who are at a higher risk for colorectal cancer. The researchers found that blood TMAO was associated with an abundance of 13 different types of gut bacteria. These included high levels of Fusobacterium, an established microbial risk factor for colorectal cancer. In addition, TMAO was related to higher insulin resistance, which often leads to diabetes.

TMAO in humans is produced entirely by gut bacteria that can convert animal food components to TMAO. The researchers reported earlier that red and processed meat is the leading food source for the TMAO precursor, choline, in a typical diet. “Since red and processed meat consumption is high in certain ethnic groups that have higher incidence rates of colorectal cancer, our study provides insight into a microbial mechanism for colorectal cancer and supports dietary interventions to reduce cancer risk and improve health disparities,” said Lim.

Each year, the EGRP Research Highlights showcase a selection of research publications supported by grants in the EGRP grant portfolio. The EGRP funds research in human populations to understand determinants of cancer occurrence and outcomes. The program is the largest funder of cancer epidemiology grants nationally and worldwide, awarding more than 240 grants and cooperative agreements annually.