Investigators may have uncovered molecular evidence of racial disparities in the receipt of precision medicine, according to a recent study published by Yamada et al in npj Precision Oncology.
Background
Colorectal cancer is the third most common cancer type diagnosed in both male and female patients in the United States. In 2022, it was the second most common cause of cancer mortality.
Precision medicine—an emerging approach in which physicians use a patient’s genetics, diseased tissue, and other factors to guide personalized treatment strategies—can dramatically improve outcomes in patients with colorectal cancer. Although analyzing cancer specimens may make such targeted therapies possible, the overwhelming majority of samples being studied in the United States and Europe are from White patients. As a result, innovative new cancer therapies may overlook genetic predispositions toward cancer that are pronounced in non-White patients.
“[Patients] from various races, regions, and communities face differences in the prevalence of cancer and survival rates from cancer,” explained lead study author Hiroshi Yamada, PhD, Assistant Professor of Research the University of Oklahoma Health Sciences Center. “Poor cancer outcomes have reasons. [However], the reasons have not been understood at the molecular level. Unlike social factors such as poverty or access to advanced cancer care, molecular differences in cancer can be addressed by a drug or other personalized treatment. [B]ecause molecular analyses on cancers historically have focused on samples from White [patients], that has created a blind spot in treatment development,” he emphasized.
Study Methods and Results
In the recent study, the investigators analyzed colorectal cancer specimens from American Indian patients residing in Oklahoma and Black patients residing in Alabama—with the goal of determining whether racial disparities in cancer could be identified at the molecular level. The investigators identified differences in gene expression and cytokines between the American Indian and Black patient groups and White patients.
Data from previous studies have shown that non-White patients often have a higher incidence rate of cancer and may experience poorer outcomes compared with White patients. Because of what researchers know about differences in gene expression and cytokines, some of the colorectal cancer drugs under development—which have been predominantly based on data from the tumor samples of White patients—may be less effective for American Indian patients and Black patients.
Additionally, the investigators revealed that racial and ethnic groups may share biological patterning that occurs as a result of social constructs rather than unchangeable characteristics as well as dietary habits, geographic locations, and other cultural practices and lifestyles. They stressed that it is essentially impossible to separate these elements that comprise biological patterning, but from the standpoint of research, race is a critical trait to consider.
Conclusions
“This study highlights potential targets for [colorectal] cancer prevention and treatment in American Indian and [Black patients], which is information that would not be available through the analysis of cancer specimens from White [patients] alone,” Dr. Yamada indicated.
The investigators hope their new findings raise awareness about the shortage of cancer specimens from non-White patient populations and bolster the effort to diversify samples for research. They plan to further examine the function of genes that could be influencing colorectal cancer development and treatment outcomes in American Indian and Black patients.
“Molecular analysis is a new research tool in the field of cancer disparities. Molecular analysis according to race, or any population vulnerable to cancer, will help to identify specific cancer traits—which can be used in the development of precision medicine. This approach will improve poor health outcomes in minorities who have cancer,” concluded Dr. Yamada.
Disclosure: The research in this study was funded by the National Institutes of Health. For full disclosures of the study authors, visit nature.com.
