New research to be presented today (Monday) at the annual meeting of the European Society of Human Genetics shows that a cancer patient’s genetic ancestry can have a significant impact on both disease progression and survival. In the largest study of its kind, researchers looked at about 1,900 specific genetic changes in tumors to determine whether certain mutations are more common in patients of different historical and geographic origins.
Presenting the results, Yixuan He, Ph.D., assistant professor of epidemiology at the University of Texas Health Science Center in Houston, Texas, USA, explained how he, in collaboration with doctoral student Jiawei Tu, analyzed genetic sequence data from more than 30,000 patients from two large cancer centers: Dana-Farber (Boston, Mass.) and MD Anderson (Houston). The data covered five different cancers: breast cancer, colorectal cancer, glioma (the most common type of brain tumor), pancreatic cancer, and lung cancer. In addition to looking at mutations, the researchers also took into account environmental factors such as socio-economic status and air pollution to ensure the results were not skewed. They then created a scoring system based on genetic mutations to predict which patients were likely to die from cancer and tested whether combining ancestry information could improve predictions.
Predictive scoring has been done before, but this is the first time this type of analysis has been performed at this scale.
Previous studies have been limited to single populations and small populations of single tumors, and often did not take into account environmental factors or long-term clinical outcomes. By expanding the scope of our research, we hoped to demonstrate the real, measurable impact that genetic ancestry has on cancer genomics and clinical outcomes. ”
Dr. Yixuan He, Assistant Professor of Epidemiology, University of Texas
The results show dozens of common mutations that are more or less prominent depending on a patient’s ancestry, about half of which could be targeted with existing treatments. This scoring system was able to predict patient survival, especially in breast cancer and glioma. Adding ancestry information made survival predictions more accurate, especially for pancreatic cancer.
Tumor sequencing is relatively common in modern cancer treatment, and its integration does not require additional cost or testing, as genetic ancestry can be inferred from these data. Environmental factors can also be simply estimated based on where the patient lives. “The integration challenge does not come from a lack of appropriate technology, but from a workflow that can derive these critical elements from existing routine data collection,” says Dr. He. “We are currently working with oncologists in hopes of overcoming these barriers.”
The researchers now plan to expand their analysis to include other cancers, incorporate additional environmental factors such as smoking and other pollutants, and ideally plan to collaborate with other groups to replicate their findings in other patient cohorts. Although some of their conclusions were already known, they were also able to identify some new associations, for example overexpression (enrichment) of genes involved in controlling cell proliferation.CDK6) in African American breast cancer patients, SMAD2another cell growth regulator gene in American colorectal cancer patients with mixed ancestry.
“It was very encouraging that a consistent ancestry-related signal was reproduced between the two different biobanks despite geographic and population differences. By identifying specific genetic markers associated with ancestry, we could pinpoint mutations to target and “Validating these signals across different populations can help ensure that specific treatments are adaptable and effective for diverse patients.” Dr. He concludes.
Professor Alexandre Raymond, chair of the conference who was not involved in the study, said: “This study convincingly shows that in order to fully personalize healthcare and help the greatest number of patients, we need to assess disease risk in diverse populations.”
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European Society of Human Genetics
