About Biomarkers

Knowing your colorectal cancer biomarkers can help your doctors identify your best treatment options and help you in making well-informed decisions about how your cancer will be treated. Knowing your biomarkers will allow you to be your own best advocate.

In terms of cancer, biomarkers, short for biological markers, provide vital information about your tumor. Biomarker testing is also often called Tumor Testing when referring to cancer treatment. Typically, biomarkers are either a protein or antibody (molecule) released by a tumor, or they are a body’s response to the presence of cancer, which could show up as a gene mutation.

Your colon or rectal tumor might not respond to the same treatment that other colorectal cancer patients receive, depending on the genomic changes within your tumor. Addressing your course of treatment by learning the specific genomic changes of your cancer—your colorectal cancer biomarkers—will help your team deliver specific care that will be the most beneficial with the least amount of side effects. Learn more about specific colorectal cancer biomarkers below.

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Colorectal Cancer Biomarkers

















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Things to consider when choosing treatment

It’s vitally important to talk to your doctors about your colorectal cancer biomarkers (aka tumor type), as soon as possible after your diagnosis and before treatment begins. This information can help you make the best treatment decisions. It’s also important to consider the following factors before beginning treatment.

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Frequently Asked Questions

  • What is the process of biomarker testing?

    Biomarker tests are done by analyzing biopsies to identify gene mutations. After the biopsy is collected it will be analyzed by a pathologist who will look for abnormalities and report back to your doctor. The pathologist will report on prognostic biomarkers, used to describe the course of a patient’s disease, and predictive biomarkers which may determine if a patient will respond well to a particular treatment. For patients who are monitoring cancer after active treatment, it is likely they will only report on recurrence.

    For more information on biomarker testing and colorectal cancer biomarkers in general, request a packet.

  • How do I know if my tumor has been tested?

    Talk to your doctor to find out if your tumor has been tested for biomarkers.

  • What if my tumor wasn't tested and I'm already receiving treatment?

    Biomarker testing should happen as close to your diagnosis as possible, before selecting a treatment plan. If you begin receiving a treatment before knowing your tumor type, this may exclude you from future treatment options, including some clinical trials. Take the time to talk to your doctor about tumor testing before making treatment decisions.

    Even if it’s been years after diagnosis or you’re currently on treatment, it’s important to know if you’ve had your biomarkers tested!

  • What is the difference between a tumor biopsy and a liquid biopsy?

    Tumor biopsy is the removal of cells or tissues from the tumor to be examined by a pathologist. There are incisional biopsies where only a sample of tissue is removed, and excisional biopsies, where the entire tumor is removed.

    Liquid biopsy is a sample of blood that pathologists use to look for DNA from tumor cells or tumor cells circulating in the blood. They are looking for circulating tumor DNA (ctDNA) and/or circulating tumor cells (CTCs). Liquid biopsies can be used to help plan treatment or learn if a treatment is working, or if the cancer has returned.

  • I've had genetic testing. Does this mean I've had biomarker testing?

    Genetic testing is a type of biomarker testing, but does not ensure that you have received all the biomarker tests necessary to make an informed treatment decision.

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All medically-reviewed content was written, edited and produced by Fight Colorectal Cancer


This educational resource was made possible thanks to the support of Bayer.

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Biomarked is dedicated to the memory of Clint Cummings, owner of Sparrows Tattoo Company and stage IV colorectal cancer fighter. Clint was passionate about raising awareness with his story. Biomarked uses tattoos to create awareness about a lifesaving topic for colorectal cancer patients and works to break the still-present taboo surrounding colorectal cancer to get people’s attention.

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The information and services provided by Fight Colorectal Cancer are for general informational purposes only and are not intended to be substitutes for professional medical advice, diagnoses or treatment. If you are ill, or suspect that you are ill, see a doctor immediately. In an emergency, call 911 or go to the nearest emergency room. Fight Colorectal Cancer never recommends or endorses any specific physicians, products or treatments for any condition. This site does not serve as an advertisement or endorsement for any products or sponsors mentioned.


The evidence-based guideline for molecular testing for colorectal cancer is a joint publication between the four organizations: American Society for Clinical Pathology, College of American Pathologists, Association for Molecular Pathology, and American Society of Clinical Oncology
The complete title of the guideline is: Molecular Biomarkers for the Evaluation of Colorectal Cancer Guideline From the American Society for Clinical Pathology, College of American Pathologists, Association for Molecular Pathology, and American Society of Clinical Oncology

Martin V, Landi L, Molinari F, et al. HER2 gene copy number status may influence clinical efficacy to anti-EGFR monoclonal antibodies in metastatic colorectal cancer patients. Br J Cancer. 2013;108:668–675.

National Comprehensive Cancer Network. https://www.nccn.org/

Siena S, Sartore-Bianchi A, Lonardi S, et al. Trastuzumab and lapatinib in HER2-amplified metastatic colorectal cancer patients (mCRC): The HERACLES trial. J Clin Oncol. 2015;33 abstract 3508.