DNA testing alone can produce inconclusive, unhelpful results on whether a genetic variant (an error in our DNA) increases the risk for cancer. Moreover, standard DNA testing for hereditary cancer excludes large portions of DNA, thereby missing variants that cause increased risks for cancer. Adding RNA to DNA testing overcomes these limitations for a significant number of patients as RNA provides considerably more evidence than DNA alone about whether the genes in our DNA have variants that cause increased risks for cancer. Clinicians can then use this information with patients and their relatives to try to prevent cancer from developing or to detect cancer early.
“We developed paired RNA and DNA testing to provide more accurate and conclusive results that patients and doctors can act on,” said Aaron Elliott, PhD, CEO of Ambry Genetics. “With +RNAinsight, we not only identify mutations that DNA testing alone would miss, we also provide answers for patients who have been dealing with inconclusive results for years.”
This year, almost 700,000 people in the United States are expected to turn to clinical labs for clinical-grade genetic testing to learn whether they have genetic mutations linked with increased risks of cancer. By pairing RNA and DNA testing, it is estimated +RNAinsight may help more than 16,000 of these individuals get the genetic information they need that they might not get from DNA testing alone.
In fact, +RNAinsight will actually help more than these 16,000 individuals because this number does not include their relatives who can then be tested to learn of their own increased risks. Nor does it include patients previously tested who had received inconclusive results from DNA testing alone and will now receive reclassification reports based on +RNAinsight.
“Paired RNA and DNA genetic testing is a remarkable leap forward. My patients are finally getting answers I was unable to provide before,” said Huma Rana, MD, Clinical Director of Cancer Genetics and Prevention at Dana Farber Cancer Institute. “In our short time using this technology, we have made meaningful changes to patient care.”
A prospective analysis of the first 2,500 patients tested with paired RNA and DNA hereditary cancer testing for up to 18 genes, sent in from pilot clinical sites, resulted in a relative increase in diagnostic yield of approximately seven percent. The impact on diagnostic yield varies by gene, with some genes having a relative diagnostic yield increase of over 15%. BRCA1, PMS2, MSH2, and ATM are among the genes for which we are seeing a greater impact. Thus, paired testing will now let many more patients with mutations in high-risk cancer genes know this when DNA testing alone would not have done so. These patients will now benefit from preventive steps, early detection, reduced cancer incidence, and increased survival, as will their relatives who get tested.
“Paired RNA and DNA testing has meant everything to me and my family in our fight against cancer, finally letting my brother, sister, and me know we have a genetic mutation that causes Lynch syndrome, which puts us at an increased risk for colorectal and uterine cancers,” said Turkeesa Looper. “Past DNA tests never told us that, and now our family, including my nieces and nephews, can also take action.”
Additionally, the data illustrates +RNAinsight’s ability to clarify results that were previously deemed inconclusive as a result of DNA testing alone. +RNAinsight was able to decrease the number of inconclusive results across the included cancer risk genes by approximately five percent relative to DNA testing alone.
+RNAinsight builds on an earlier breakthrough in RNA genetic testing that Ambry led. For three years, Ambry has offered RNA testing retrospectively – looking at RNA after DNA testing was complete. While helpful, retrospective RNA testing has limitations that +RNAinsight does not, such as not being able to identify mutations that the earlier DNA testing failed to find and patients who are lost to follow-up.
+RNAinsight is now available through doctors and genetic counselors around the country. For more information on paired RNA and DNA testing, please go to www.ambrygen.com/RNAinsight. For more information on risk factors for hereditary cancer, please visit cancer.gov’s fact sheet on hereditary cancer and genetic testing.
Source: Cancer, Ambry. 2019. "Ambry Genetics Makes Scientific Breakthrough And Launches Paired RNA And DNA Testing For Hereditary Cancer". Ambrygen.Com. https://www.ambrygen.com/about/press-release/118/ambry-genetics-makes-scientific-breakthrough-and-launches-paired-rna-and-dna-testing-for-hereditary-cancer.