Biomarker Testing for Genetic Mutations in Colorectal Cancer
No two cases of colorectal cancer are exactly alike. While the stage and location of the cancer remain important factors in determining the most effective treatment plan, today’s cancer care also looks at the unique biology of the tumor itself. The Cancer Care Centers of Brevard oncologists use biomarker testing to determine which treatments will be most effective for their patients.
Biomarker testing provides valuable information about specific genetic and molecular changes (biomarkers) within colorectal cancer cells. Genetic mutations are categorized as somatic or germline. Germline mutations are inherited, and somatic mutations are caused by external factors that develop in a person’s lifetime. Biomarker testing is specifically looking for somatic genetic changes that occurred in the patient’s cells.
Several gene mutations are associated with the development of colon and rectal cancers. Some patients may have no detectable genetic mutations, while others may have one or several gene mutations. Based on biomarker test results, your oncologist identifies which therapies are likely to work best.
How are Colorectal Cancer Biomarkers Identified?
Biomarkers have measurable characteristics, such as proteins, genes, and other substances, that provide insight into tumor behavior. A sample of tissue removed during surgery or a biopsy is examined to look for those unique characteristics. Sometimes, a blood test may be used.
The results of biomarker testing provide helpful information about your specific type of colorectal cancer. This allows your care team to tailor the most effective treatment plan for you, which may include access to targeted therapies, immunotherapies, and potential clinical trial opportunities.
Types of Biomarker Tests for Colorectal Cancer
There are two primary types of biomarker testing used in colorectal cancer:
Genetic Biomarker Tests
Genetic biomarker testing analyzes various genes that may influence how colorectal cancer grows and responds to treatment. Your treatment plan may be adjusted based on the results of these tests.
Common genetic biomarkers tested in colorectal cancer include: BRAF, KRAS, NTRK, and HER2. As research continues to advance, additional biomarkers may become part of routine testing.
Protein Biomarker Tests
Some biomarkers measure proteins rather than gene mutations.
One of the most common is CEA (carcinoembryonic antigen), a protein that can become elevated when the colon is inflamed. Higher CEA levels are often found in people diagnosed with colorectal cancer.
Additional Biomarker Tests That Help Guide Colorectal Cancer Treatment
Your oncologist may also evaluate other tumor characteristics that provide important treatment information.
Tumor Sideness
Sideness refers to whether the tumor developed on the right or left side of the colon. Right-sided and left-sided colon cancers typically have different biological characteristics and may respond differently to certain treatments.
Pathways
Pathways, or signaling pathways, evaluate how cancer cells behave and communicate. Biomarker pathways that may be tested include the PD-L1 pathway, tumor mutational burden (TMB), and the WNT pathway.
Is Biomarker Testing Used for All Colorectal Cancer Patients?
The biomarker tests recommended for each patient depend on the stage of the colorectal cancer and whether the disease has returned after treatment.
Testing may be recommended for:
Patients newly diagnosed with colorectal cancer of any stage to evaluate microsatellite stability (MSI-H/dMMR) status. Several approved immunotherapy drugs are available to help slow the growth of cancer cells with high MSI-H biomarkers.
Patients with stage II, III, or IV colorectal cancer who may benefit from CEA monitoring during treatment and follow-up. Tracking CEA over time can help identify recurrence and provide additional information about the tumor, which may prove helpful for treatment.
Patients diagnosed with metastatic (stage IV) colorectal cancer are often tested for genetic alterations such as BRAF, KRAS, NRAS, NTRK, and HER2. If one or more of these biomarkers are present, targeted therapies may be available to slow the growth of cancer.
If you have already had surgery or a biopsy, your colorectal cancer specialist can review whether biomarker testing has already been done or if additional testing is needed.
How Biomarker Testing Supports Personalized Cancer Care
As cancer research advances, new treatments make it possible to personalize care more than ever before. Instead of using a one-size-fits-all approach, biomarker testing, often called precision medicine, helps physicians customize treatment to the unique characteristics of each patient’s tumor.
Identifying biomarkers can help determine whether targeted therapies may be effective in slowing or destroying cancer cells while minimizing damage to nearby healthy cells. Because each patient’s cancer is unique, treatment recommendations may vary based on the biomarkers that are present. After reviewing your biomarker testing, your colorectal cancer specialist will discuss the recommended next steps in your care.
Personalized Colorectal Cancer Care Based on Genetic Mutations in Brevard County, Florida
At Cancer Care Centers of Brevard, we use the latest advances in biomarker testing and precision medicine to help guide treatment decisions for patients with colorectal cancer. Our experienced colorectal cancer specialists develop treatment plans based on each patient's unique needs and biomarker test results.
Whether you've been recently diagnosed with colorectal cancer, have recurrent colorectal cancer, or are seeking a second opinion, our team is here to help you understand your options and provide you with comprehensive care every step of the way. Our oncologists are located throughout Brevard County, including Melbourne, Merritt Island, Rockledge, and Palm Bay, Florida.