Liquid biopsy offers noninvasive DNA testing for cancer care

Answers from the Lab

DNA tumor testing is key to providing individualized cancer treatment. In this test specific episode of the "Answers From the Lab" podcast, Gang Zheng, M.D., Ph.D., and Aaron Mansfield, M.D., describe Mayo Clinic Laboratories’ liquid biopsy, which detects single nucleotide variants, insertions and deletions in the 33 target genes listed in guidelines. The assay also assesses gene amplifications, translocations and microsatellite instability.

"NGS testing using tissue biopsies is considered a gold standard. But liquid biopsy can also capture tumor heterogeneity and has some advantages over cell-based testing," Dr. Zheng says.

Advantages include:

  • Noninvasiveness
  • Faster turnaround time
  • The ability to perform molecular testing in patients when tumor tissue isn’t available

Liquid biopsy can be a more viable option for certain individuals. "Patients might be anticoagulated or have disease in a location that's difficult to stick a needle into," Dr. Mansfield says. "If the disease is primarily metastatic to the bone, decalcifying those specimens might degrade the DNA, making it inappropriate for processing."

Dr. Mansfield notes that many of the genetic mutations included in the liquid biopsy panel —such as RET, ALK fusion and BRAF V600E mutation — have associated therapies approved by the Food and Drug Administration.

Liquid and cell-based biopsies complement each other in patient care. "This liquid biopsy test will enhance the genomic profiling capability of our lab," Dr. Zheng says. "The DNA assay offers our physicians and their patients a noninvasive, comprehensive mutation-profiling option to guide clinical treatment."

Listen to learn more about Mayo Clinic Laboratories' liquid biopsy for cancer care.

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Useful information

  • As an alternative to invasive tissue biopsies to assist in tumor profiling for diagnosis, predicting prognosis, and identifying targeted therapies for the treatment and management of patients with solid tumors.
  • As an alternative to invasive tissue biopsies for assessment of microsatellite instability status.

Specimen requirements

  • Specimen Type: Whole Blood
  • Container/Tube: Streck Cell-Free DNA (cfDNA) blood collection kit
  • Specimen Volume: Two 10-ml Streck Cell-Free DNA blood collection tubes

Additional Information: Only blood collected in Streck Cell-Free DNA BCT tubes will be accepted for analysis. Whole blood will be processed to produce platelet-poor plasma before cfDNA isolation.

Performance information

Analytic time: 7 days

Days performed: Monday through Friday

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Barbara J. Toman

Barbara J. Toman is a Senior Communications Specialist at Mayo Clinic Laboratories. She is also the science writer for Mayo’s Neurosciences Update newsletter, which helps referring physicians to stay informed about Mayo’s treatment and research. Barbara has worked at Mayo Clinic since 2007. She enjoys international travel and cooking.