Black Cancer Patients Have Lower Quality Genomic Sequencing Data

March 21, 2022 - Mayo Clinic researchers examined the Cancer Genome Atlas and found that Black patients received lower-quality genomic sequencing, leading to less complete data and a weak DNA database, according to a study published in the Journal of the National Cancer Institute.

For the study, researchers studied various types of cancer, considering several factors such as sequencing depth, tumor purity, and the quality of germline variants and somatic mutations. The tumor groups used included data from over 50 patients of African ancestry.

"We found lower quality genomic sequencing data in self-reported Black patients and patients of African ancestry," said Yan Asmann, PhD, a Mayo Clinic bioinformatician and senior author of the study, in the press release.

Specifically, researchers found that germline and tumor exomes from Black patients were sequenced at a significantly lower depth in six out of the seven cancers studied, Asmann said.

"Lower sequencing depths of tumor and germline exomes likely resulted in less-complete data, underdetection of germline variants and somatic mutations, and inferior variant quality among patients with African ancestry," she said.

Researchers concluded that the restructuring of genomic cancer studies is necessary.

"This finding serves as a reminder that when designing, conducting, and interpreting genomic cancer studies, the underlying data quality differences between patients need to be carefully examined,” Asmann said.

Often, the genetic variants examined do not include minority groups, such as people of African descent.

"These data highlight the need to consider epidemiological factors when designing and conducting future genomic and genetic studies," said Asmann. "The scientific community and the Cancer Genome Atlas may consider resequencing residual DNA, if still available, from these Black patients with cancer with confirmed African ancestry, or additional ancestrally African patients could be sequenced at high coverage to compensate for the current disparity."

Racial disparities frequently emerge when collecting data, leading to inaccurate statistics and poorer health outcomes for minority populations.

For example, a report from January describes how these disparities can lead to increased death rates across the country. Across 30 large cities in the U.S., the Black population experienced a 24 percent higher mortality rate than White populations. Reviewing and restructuring approaches related to childhood development and environmental conditions can improve health equity.

Another study from February 2020 shows that asthma patients who are part of a racial minority have a higher likelihood of visiting the emergency department. To combat the issue, researchers collected data from the 2015 Behavioral Risk Factor Surveillance Survey and the Asthma Call-Back Survey and used this information to conduct a regression analysis. The goal of the study was to control and monitor the social risk factors associated with racial minorities ending up in the emergency department more often than their White counterparts.