Precision Medicine May Not be Beneficial for All Patients

Gaps in genome sequencing can lead to misdiagnosis for patients of non-European descent.

Precision medicine has been heralded as a groundbreaking approach to treat potentially life-threatening diseases, including cancer. For oncology, precision medicine involves conducting genetic tests to determine the most targeted treatment strategy.

Despite the promise of precision medicine, a new study published by BMC Medical Genomics suggests that it may not be beneficial for patients of non-European descent.

Identifying the genetic mutations that drive cancer is crucial for proper treatment. Ideally, physicians are able to compare variations to a patient’s own healthy tissue, but if healthy tissue is not available, population databases have to be used, according to the study.

The authors caution that patients whose cancer cell sequencing cannot be compared to normal cells have an increased risk of misdiagnosis.

“The field of precision medicine isn’t taking into account population differences. The approaches being used are imprecise when you look at very specific populations,” said lead author John Carpten, PhD.

Using a tumor-only approach to inform treatment was observed to be inaccurate for patients with Latin American, African, and Asian descent, according to the study.

“You might be getting the wrong therapy simply because of our lack of understanding of the genetic architecture of your ancestry,” said senior study author David W. Craig, PhD. “These findings argue that we’re really not doing a very good job of doing precision medicine for many populations.”

Some hospitals may collect cancer tissue for research without also sampling healthy tissue, which may prevent investigators from determining which mutations are cancer-causing and which are benign.

“It is very difficult to identify a somatic, or potentially cancer-causing, variant when you don’t have a germline, or normal, sample,” said lead author Rebecca Halperin, BSc.

Another issue is that a majority of individuals who have underwent whole-genome sequencing are of European descent. This factor may cause significant bias in current databases, according to the study.

Notably, those with European ancestry are the least ethnically diverse, meaning there are few genetic variants, according to the study. The authors said these findings highlight the necessity of sampling a more diverse population.

The authors noted that individuals who are from less developed regions have the most diverse genomes, making them important for improving precision medicine.

“This study goes beyond the barriers to participation and provides insight on the lack of genetic data from diverse populations and its impact on the value and utility of precision medicine,” said researcher Rick Kittles, PhD. “There is still much work to be done in order for all communities to benefit from precision medicine.”

These findings call for novel ways to make precision medicine more accurate, according to the study.

“Simply sequencing more individuals from various populations is not enough,” Craig said. “We really need access to the cells that were passed on from previous generations. But when those aren’t available, we need better tools.”