Researchers identify new gene mutations linked to colorectal cancer in African-Americans

Discovery paves way for new approaches for population with highest incidence and mortality rates from this kind of cancer

Case Comprehensive Cancer Center researchers have identified new gene mutations unique to colon cancers in African Americans - the population with the highest incidence and death rates of any group for this disease.

This discovery - namely, that colorectal cancers appear different on a molecular level in African Americans - offers new hope for these patients. With this groundbreaking knowledge, scientists now will seek to develop treatments that target the distinct nature of the disease in African Americans - and, they hope, begin to reduce the devastation disproportionately wrought on this population.

The findings, published in the Jan. 12 edition of PNAS (Proceedings of the National Academy of Sciences), only became possible because of technological advances in gene sequencing and computational analysis. The study that revealed this invaluable information ultimately involved review of 1.5 billion bits of data.

"This milestone study builds on our previous genetic research on colorectal cancer," said Sanford Markowitz, MD, PhD, corresponding author on the study, and principal investigator of the $11.3 million federal gastrointestinal cancers research program (GI SPORE) that includes this project. "It illustrates the extraordinary impact that dedicated, collaborative teams can make when they combine scientific experience and ingenuity with significant investment."

Announced in 2011, this GI SPORE program is one of just five in the country. Markowitz, Ingalls Professor of Cancer Genetics at Case Western Reserve School of Medicine and a medical oncologist at University Hospitals Case Medical Center, included studies of the disease's behavior in minority patients as part of his team's original grant application. The disparity between colorectal cancer rates in African Americans and other groups has long existed; the most recent federal statistics, for example, put age-adjusted incidence at 46.8 cases for every 100,000 African Americans, and 38.1 cases for every 100,000 Caucasian Americans. Yet scientists have struggled to determine what factors - biological, economic, environmental, or others - account for this disparity.

"These advancements underscore the importance of university-based research," said Congresswoman Marcia L. Fudge, former chair of the Congressional Black Caucus and representative of the 11th district, which includes Case Western Reserve and UH Case Medical Center. "I am proud that researchers from Northeast Ohio are taking meaningful steps toward identifying pathways to block a devastating disease that disproportionately affects members of the African American community."

From the very start, Markowitz and his colleagues believed the answer to this question would be found through genetic analysis.

"Identifying gene mutations has been the basis of all the new drugs that have been developed to treat cancer in the last decade," Markowitz said. "Many of the new cancer drugs on the market today were developed to target specific genes in which mutations were discovered to cause specific cancers."

One of the lead researchers on the project was senior author Joseph E. Willis, MD, associate professor of pathology, Case Western Reserve School of Medicine, director of tissue management, Case Comprehensive Cancer Center, and Vice Chair of Pathology for Clinical Affairs at UH Case Medical Center.

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Researchers identify new gene mutations linked to colorectal cancer in African-Americans