Colorectal panel provides detailed cancer information  

Answers from the Lab

New information about colorectal cancer has led to updated recommendations for testing and treatment. In this test specific episode of the "Answers From the Lab" podcast, Rondell Graham, M.B.B.S., describes Mayo Clinic Laboratories' expanded colon panel, which provides enhanced information about prognosis, treatment options and a hereditary cancer syndrome.

"This new expanded panel allows us to address patient needs. It covers a larger number of genes and provides a greater amount of clinically actionable information," Dr. Graham says.

In addition to covering multiple gene mutations, the assay assesses for microsatellite instability and Lynch syndrome. Microsatellite instability is a biomarker for response to checkpoint inhibitor treatment. The American Society of Clinical Oncologists recommends that testing for Lynch syndrome — an inherited cancer syndrome — be performed for all people diagnosed with colorectal cancer.

The MayoComplete Colorectal Cancer Panel uses next generation sequencing and is suitable both for patients with cancer confined to the colon and for cases of metastatic colorectal cancer.

"Being able to address all these patient needs and gain so much useful information in a single assay will be very helpful," Dr. Graham says.

Listen to learn more about Mayo Clinic Laboratories' expanded MayoComplete Colorectal Cancer Panel.

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Useful information

  • Diagnosis and management of patients with colorectal cancer
  • Assessment of microsatellite instability

Specimen requirements

This assay requires at least 20% tumor nuclei

  • Preferred amount of tumor area with sufficient percent tumor nuclei: tissue 216mm(2)
  • Minimum amount of tumor area: tissue 36mm(2)
  • These amounts are cumulative over up to 10 unstained slides and must have adequate percent tumor nuclei
  • Tissue fixation: 10% neutral buffered formalin, not decalcified

For specimen preparation guidance, see Tissue Requirement for Solid Tumor Next-Generation Sequencing. In this document, the sizes are given as 4mm x 4mm x 10 slides as preferred: approximate/equivalent to 144 mm(2) and the minimum as 3mm x 1mm x 10 slides: approximate/equivalent to 36mm(2).


  • Specimen Type: Tissue block
  • Collection Instructions: Submit a formalin-fixed, paraffin-embedded tissue block with acceptable amount of tumor tissue


  • Specimen Type: Tissue slide
  • Slides: 1 stained and 10 unstained
  • Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 10 unstained, nonbaked slides wit 5-micron thick sections of the tumor tissue

Note: The total amount of required tumor nuclei can be obtained by scraping up to 10 slides from the same block

Additional Information: Unused unstained slides will not be returned

Performance information

Analytic time: 12 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.