Project shows gut microbiome differences could explain racial disparities in colorectal cancer

March 02, 2017

The incidence and risk of colorectal cancer is higher in African-Americans than whites, and differences in their gut microbiomes may be the culprit, according to researchers involved in a gut microbiome project at the Wayne State University School of Medicine.

Ziad Kanaan, M.D., Ph.D., a second-year gastroenterology fellow in the Department of Internal Medicine, will outline the discovery at the North American Conference of GI Fellows meeting March 17-19 in Orlando, Fla.

His abstract, “Alteration in Gut Microbiome Could Partly Be Responsible for Racial Disparity in Colorectal Cancer,” was one of only 25 selected for a podium presentation at the event.

“Our work showed that differences in the gut microbiome between African-Americans and Caucasians could result in changes in the intestinal secondary bile salts – which are known for their tumorigenic effect – and could thus be partially responsible for racial disparity in colorectal cancer,” Dr. Kanaan said.

Colorectal cancer is nearly twice as common in African-Americans younger than 50 than their white counterparts, according to the National Cancer Institute. Young-onset African-Americans in as early as stage II of the disease also have a 60 percent to 70 percent higher risk of death than whites.

Dr. Kanaan completed the work while working in the lab of his mentor, Professor of Internal Medicine Adhip Majumdar, Ph.D.

“Dr. Majumdar continues to provide me with insight about career grant opportunities and mentorship regarding academic GI opportunities following graduation. I would like to also thank Associate Professor of Internal Medicine Fadi Antaki, M.D., who was providing us with the clinical samples and very insightful critique regarding the clinical applications of our research work,” Dr. Kanaan said.

The outcome highlights the significance of the gut microbiome and underlines the importance of certain diet choices on such risks.

“Eventually, this could provide potential areas of intervention to prevent colorectal cancer at a public health scale,” he said. “Human microbiome research has been gaining a lot of momentum due to recent findings relating it to human health and disease, including colorectal cancer.”

Dr. Kanaan was already familiar with Dr. Majumdar’s work with microRNAs as potential potent gene regulators in colorectal tumorigenesis.

“This coincided with my Ph.D. work, and I was thrilled to carry on this line of work at Dr. Majumdar’s laboratory,” he added.

Research Scientist Lulu Farhana, Ph.D.; Associate Professor of Oncology Pratima Nangia-Makker, Ph.D.; and Research Assistant Professor of Internal Medicine Yin Ji Yu, M.D., also contributed to the project.

Dr. Kanaan will also present the research at the Digestive Disease Week meeting May 6-9 in Chicago.

“This project is a building block of a line of work I intend to continue at Dr. Majumdar’s laboratory in my third year, and hopefully in the future,” he said.

He completed his Internal Medicine residency with the WSU School of Medicine. He holds a medical degree from the American University of Beirut and a doctorate from the University of Louisville.

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