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Biomarkers & Tumor Markers

Biomarkers and tumor markers play a central role in how we deliver precise, personalized cancer care at NewYork-Presbyterian. These tests look for specific molecules in your blood or tissue that can reveal important information about your cancer, from confirming a diagnosis to identifying targeted treatment options and monitoring how well therapy is working.

What are biomarkers & tumor markers?

What are biomarkers & tumor markers?

Biomarker testing helps our oncology care teams deliver the right treatment by identifying specific genes, proteins, or other molecular features in a tumor.

Biomarkers - Biological molecules found in blood, tissue, or other body fluids that provide information about a cancer.

Tumor markers - type of biomarker that is produced by cancer cells, or by the body in response to cancer, and can sometimes be measured in the blood.

Liquid biopsy - A blood test that looks for cancer-related material, such as circulating tumor DNA (ctDNA), shed by cancer cells into the bloodstream.

Tissue biopsy - A procedure in which a small sample of tissue is removed from a tumor or suspicious area and examined under a microscope.

Molecular testing - Laboratory testing performed on cancer cells to identify specific genes, proteins, or other molecular features that drive tumor growth.

Genomic profiling - A comprehensive type of molecular testing that analyzes many genes at once to identify mutations or alterations in a tumor’s DNA and create an actionable, personalized treatment plan.

More to explore

How is molecular testing done?

How is molecular testing done?

Testing for cancer biomarkers can be performed through either a tissue biopsy or a liquid biopsy, depending on your diagnosis, treatment stage, and the information your care team needs.

Tissue biopsy

Tissue biopsy is the gold standard for diagnosing most cancers. Our specialists use a range of approaches tailored to the type and location of the suspected cancer and each patient’s individual needs.

Your care team may use minimally invasive, image-guided techniques to perform a biopsy. These methods allow providers to collect a tissue sample with minimal discomfort and quick recovery.

A pathologist then examines the sample under a microscope to confirm the diagnosis. The same tissue can also be used for molecular testing or genomic profiling to identify specific mutations or protein markers that may guide treatment decisions.

A liquid biopsy is a blood test that looks for cancer-related material that tumors shed into the bloodstream.

Liquid biopsy

A liquid biopsy is a blood test that looks for cancer-related material that tumors shed into the bloodstream.

In many situations, liquid biopsy will complement a tissue biopsy. Your care team will determine which approach, or combination of approaches, is most appropriate for your specific cancer and treatment plan.

Liquid biopsy vs. tissue biopsy

Tissue biopsies are typically used for:

  • Confirming a cancer diagnosis
  • Determining cancer type and subtype
  • Performing comprehensive molecular or genomic testing
  • Evaluating tumor characteristics such as grade or receptor status

Liquid biopsies are typically used for:

  • Identifying certain genetic mutations when tissue is limited or difficult to obtain
  • Monitoring how well treatment is working over time
  • Detecting emerging resistance mutations
  • Tracking for signs of recurrence
  • Identifying the tissue of origin for some cancers of unknown primary

What molecular testing results mean

What molecular testing results mean

Biomarker and tumor marker tests can provide powerful insights, but they are not a standalone diagnosis or treatment plan. Specialists consider your biomarker findings alongside your diagnosis, imaging results, pathology report, overall health, and personal treatment goals when determining what your results mean and how they should inform your care. 

In some cases, biomarker testing can open the door to targeted therapies or clinical trials that would not otherwise be considered. Depending on the type of cancer and the test performed, results may help your care team: 

  • Confirm certain characteristics of a tumor 
  • Identify genetic mutations or protein markers that may be targeted with specific therapies 
  • Determine whether immunotherapy is likely to be effective 
  • Monitor how well treatment is working 
  • Detect early signs of recurrence or treatment resistance 

What results can’t tell you 

Not every cancer has identifiable or actionable biomarkers. Even when a mutation or marker is found, there may not always be a targeted therapy available. In addition: 

  • A normal tumor marker level does not always mean cancer is absent, just as an elevated tumor marker does not automatically mean cancer is present or progressing. 
  • Liquid biopsy tests may not detect all mutations, especially if very little tumor DNA is circulating. 

What happens after biomarker testing?

What happens after biomarker testing?

If your care team finds a biomarker that is linked to an available therapy, they may recommend a targeted therapy designed to act on that specific genetic change. Immunotherapy may be considered as an option if your markers suggest it may be effective. Your care team may also evaluate your eligibility for clinical trials studying new therapies. The goal of targeted treatments is to interfere with the specific molecular drivers of a tumor, which may be more effective than standard chemotherapy alone in certain cancers. 

Not all cancers have identifiable or targetable biomarkers. In these cases, standard treatments such as surgery, chemotherapy, radiation therapy, hormone therapy, or immunotherapy, may still be highly effective. Your care team will recommend evidence-based options tailored to your specific cancer. 

In some situations, biomarker testing may be repeated during or after treatment. Changes in tumor genetics can occur over time, particularly if a cancer develops resistance to therapy. Repeat testing, often through a liquid biopsy, may help identify new treatment options. 

Questions to ask your care team

Questions to ask your care team

If biomarker testing is part of your care plan, asking informed questions can help you better understand your options and feel more confident in next steps. Your oncology care team can explain how biomarker testing fits into your overall treatment strategy and help you understand what the results mean for your individual care. Here are some questions to ask your care team: 

About the test 

  • What specific biomarkers will be tested, and why? 
  • Is this testing done on tissue, blood (liquid biopsy), or both? 
  • Will biomarker testing need to be repeated later? 

About the results

  • How do these results affect my treatment options? 
  • Are there targeted therapies or immunotherapies that may work for me? 
  • Do my results suggest I may be eligible for a clinical trial? 
  • If no actionable markers were found, what are my recommended treatment options? 

Biomarker testing at NewYork-Presbyterian

Biomarker testing at NewYork-Presbyterian

At NewYork-Presbyterian, we connect our patients with cutting-edge, comprehensive testing, including genomic testing, comprehensive panels, and both tissue-based and liquid biopsy testing. As a leading academic medical center, NewYork-Presbyterian also provides access to the latest clinical trials for patients whose biomarker profiles may match investigational therapies, expanding treatment options beyond standard care.

Learn more about our testing options and programs: 

Results for standard tumor marker blood tests are typically available within a few days, while more complex molecular testing or comprehensive genomic profiling can take one to three weeks. Your care team will let you know when to expect results and will review them with you as soon as they are available. 

Yes, if biomarker testing identifies a mutation that may be inherited, such as certain changes in BRCA1 or BRCA2. A genetic counselor can help determine whether the mutation is hereditary, discuss what it means for your treatment, and explain potential implications for family members. Not all mutations found in tumors are inherited, so additional testing may be needed for clarification. 

Genomic profiling helps guide treatment for your current cancer, while genetic counseling assesses inherited cancer risk and potential implications for relatives. Genomic profiling analyzes the DNA of a tumor to identify mutations or molecular changes that may guide treatment decisions. Genetic counseling evaluates whether you may carry an inherited gene mutation that increases cancer risk.

In some cases, biomarker results can change over the course of a person’s cancer treatment. As tumors grow or are exposed to treatments such as targeted therapy, chemotherapy, or immunotherapy, new genetic mutations may develop. These changes can sometimes cause a treatment that was initially effective to stop working, a process known as treatment resistance. 

Because of this, your care team may recommend repeat biomarker testing if: 

  • Your cancer progresses or returns 
  • A treatment stops working as expected 
  • New targeted therapies become available 
  • A liquid biopsy may help detect emerging mutations 

If you are having a tissue biopsy, your care team will provide specific instructions, which may include guidance about eating and drinking beforehand, adjusting certain medications (such as blood thinners), and arranging transportation if sedation is required.

For a liquid biopsy, preparation is typically minimal. Most patients do not need to fast, but your care team will confirm whether any special instructions apply. 

Not all cancers have identifiable or actionable biomarkers. Many cancers have measurable molecular features, but not every biomarker leads to a targeted treatment option. In some cancers, biomarker testing plays a central role in guiding therapy. For example: 

  • Non-small cell lung cancer may be tested for EGFR, ALK, KRAS, and other mutations that can guide targeted treatment. 
  • Breast cancer is routinely tested for hormone receptors (ER/PR) and HER2, which influence therapy choices. 
  • Melanoma may be tested for BRAF mutations that can be treated with targeted inhibitors. 
  • Colorectal cancer may be evaluated for KRAS, NRAS, BRAF, and MSI status to guide treatment decisions. 
  • Ovarian, pancreatic, prostate, and breast cancers may be tested for BRCA1 or BRCA2 mutations, which can make certain targeted therapies an option. 

In other cancer types, standard treatments including surgery, chemotherapy, radiation therapy, or hormone therapy remain the primary approach regardless of biomarker status. 

Even when a cancer does not have an actionable biomarker, testing can still provide helpful diagnostic or prognostic information. Your oncology team will determine whether biomarker testing would be helpful based on your specific cancer type, stage, and personal history.  

 

This content has been reviewed by the following medical editors.

David Horowitz, MD