Biomarker Tests for Cancer

What are Biomarker Tests for Cancer?

Biomarker tests for cancer are specialised laboratory tests that identify specific genes, proteins, or other molecular markers associated with cancer. These biomarkers provide valuable information about the unique characteristics of a person's cancer and help healthcare providers make more informed decisions about diagnosis, treatment, and ongoing care.

Unlike traditional tests that focus on the location or appearance of a tumour, biomarker testing examines the cancer at a molecular level. The results can reveal whether a tumour is likely to respond to targeted therapy, immunotherapy, chemotherapy, or other treatment options. Biomarker testing is a key component of precision medicine, allowing cancer treatment to be tailored to each patient's individual tumour profile.

What are the Benefits of Biomarker Tests for Cancer?

Biomarker testing plays an important role in personalising cancer care and improving treatment planning. Potential benefits include:

Helps identify the most effective treatment options.
Determines whether targeted therapy or immunotherapy may be appropriate.
Reduces the likelihood of receiving treatments that are unlikely to be effective.
Supports personalised treatment plans based on the biology of the tumour.
May provide information about how aggressive a cancer is likely to be.
Helps monitor treatment response or detect disease recurrence in some cases.
May identify inherited genetic changes that could affect family members.
Can determine eligibility for certain clinical trials.

When are Biomarker Tests Recommended?

Your healthcare provider may recommend biomarker testing if you:

Have been diagnosed with certain types of cancer.
Are considering targeted therapy or immunotherapy.
Have advanced, recurrent, or metastatic cancer.
Require additional information to guide treatment decisions.
Have a cancer with multiple treatment options available.
May qualify for a clinical trial based on your tumour's molecular profile.
Have a personal or family history suggesting an inherited cancer syndrome.

What are the Different Types of Biomarker Tests for Cancer?

Several types of biomarker tests are available, and the most appropriate test depends on the type of cancer and the clinical information required. Common types include:

Genetic (DNA) testing to identify gene mutations that may drive cancer growth or influence treatment options.
Protein biomarker testing to measure proteins produced by cancer cells that may predict treatment response.
Tumour (molecular) profiling to analyse multiple genes and biomarkers within a tumour for a comprehensive molecular assessment.
Liquid biopsy to detect circulating tumour DNA (ctDNA) and other cancer-related biomarkers using a blood sample.
Immunotherapy biomarker testing to assess markers, such as PD-L1 expression or tumour mutational burden (TMB), that may indicate whether immunotherapy is likely to be effective.
Inherited (germline) genetic testing to identify genetic mutations that increase the risk of certain cancers and may influence treatment or screening recommendations.

How Do Biomarker Tests Help Guide Cancer Treatment?

After a tissue or blood sample has been analysed, the results are reviewed by your cancer care team alongside your medical history, imaging studies, and pathology findings. The information gained from biomarker testing helps determine the most appropriate treatment for your individual cancer.

For example, certain biomarkers may indicate that a targeted therapy is likely to be highly effective, while others may show that immunotherapy offers the greatest benefit. In some cases, testing can also identify treatments that are unlikely to work, helping patients avoid unnecessary side effects and delays in receiving more suitable therapies.

Biomarker testing may also provide information about the expected behaviour of the cancer, the likelihood of recurrence, and whether additional genetic counselling or family screening should be considered. As cancers can evolve over time, repeat biomarker testing may sometimes be recommended if the disease progresses or returns.

What Can You Expect After Biomarker Testing?

Biomarker testing itself usually causes little or no additional discomfort beyond the biopsy or blood test used to obtain the sample. Results are typically available within several days to a few weeks, depending on the complexity of the analysis.

Once the results are ready, your specialist will explain what they mean and discuss how they may influence your treatment plan. While not every cancer has a biomarker that can currently be targeted with medication, the information obtained can still provide valuable insights that help guide your overall care and future treatment decisions.

Are There Any Limitations or Risks of Biomarker Testing?

Biomarker testing is generally very safe, as the laboratory analysis itself carries no direct risk. However, there are some limitations to consider:

Not all cancers have identifiable or actionable biomarkers.
Some biomarkers do not yet have approved targeted treatments.
Results may not always predict how well a treatment will work.
Additional tissue samples or biopsies may occasionally be required.
Results can take several days or weeks to become available.
Some tests may not be suitable for every cancer type or stage.
Interpretation of results should always be performed by an experienced cancer specialist as part of a comprehensive treatment plan.