Biomarkers and Genomic Testing
Tools You Can Use
Liquid Biopsy/ctDNA Testing: Signatera
Liquid Biopsy/ctDNA (for MRD) Testing: Guardant Reveal
Liquid Biopsy/ctDNA Testing: Guardant360®
Tissue Testing: Immunoscore®
Questions? Feedback?

Glossary of common terms

Many of the terms you will see in this Learning Center refer to specific genetic mutations or biomarkers relevant to colorectal cancer. Check out the know your biomarker chart for more information about anything marked here with *:

  • BRAF*: a gene that can mutate in several ways that affect colorectal cancer growth and response to treatment
  • CEA*: carcinoembryonic antigen
    • A protein that can be elevated in colorectal cancer patients. Used as a “marker” to track how well treatments are working or whether cancer has returned after treatment.
  • CRC: colorectal cancer
  • ctDNA: circulating tumor DNA
    • As cancer cells grow very fast and die, they release some of their DNA into the bloodstream. We now have tests that are sensitive enough to detect and sequence these pieces of ctDNA in the bloodstream separately from the normal DNA of the patient – this is called a “liquid biopsy.” 
Image copyright National Human Genome Research Intsittute
  • HER2*: A mutation that can affect colorectal cancer response to treatment 
  • Immunotherapy (IO): A type of therapy that uses substances to stimulate or suppress the immune system to help the body fight cancer, infection, and other diseases.
  • Liquid biopsy: a test that can analyze tumor molecules or cells in various bodily fluids, including blood, urine, cerebrospinal fluid, or saliva
  • MSI-H*: Microsatellite instability
    • A biomarker found in a minority of crc cancers which can make the cancer responsive to immunotherapy
  • MSS*: microsatellite stable.
    • Colorectal cancers are either MSS or MSI-H. MSS is the “normal,” unmutated state. It is the most common form of crc, and the most difficult to treat.
  • RAS (KRAS, NRAS)*: mutations in the RAS family of genes that may indicate aggressive tumor growth
  • TMB: tumor mutation burden.
    • The total number of mutations (changes) found in the DNA of cancer cells. Knowing the tumor mutational burden may help plan the best treatment. For example, tumors that have a high number of mutations appear to be more likely to respond to certain types of immunotherapy.
  • Wild Type: A gene in its natural, non-mutated (unchanged) form. In CRC, most often used to describe the KRAS gene (“Wild-type KRAS”).