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  6. Biomarker Testing
  7. ALK

ALK and Lung Cancer

Testing for rearrangements in the ALK gene helps your doctor understand your lung cancer and recommend the best treatment for you.

ALK at a Glance:

  • ALK fusions or rearrangements are one type of lung cancer biomarker.
  • Most ALK-positive cancers occur in a type of lung cancer called non-small cell lung cancer (NSCLC).
  • Comprehensive biomarker testing can help match you to targeted treatments designed for cancers with specific gene changes.
  • You can ask for comprehensive biomarker testing during diagnosis, or if current treatment stops working.

Frequently Asked Questions about Biomarker Testing

What Is ALK-Positive Lung Cancer?

ALK stands for anaplastic lymphoma kinase. It is a gene that is involved in how cells grow. Changes (fusions or rearrangements) in this gene can cause cancer.

The ALK gene is in your body while you are still an embryo, helping your gut and nervous system develop. It typically turns off before you are born. For some people, however, the ALK gene will turn back on and fuse, or join, with another gene. This gene change is called an ALK fusion or ALK rearrangement, and it can cause cancer. When this fusion or rearrangement happens, a patient is said to be ALK-positive. 

The most common gene that ALK fuses with is called EML4. Depending on exactly where the ALK and EML4 genes join, there are different types of EML4-ALK fusions.

In this video, Dr. Ross Camidge explains what an ALK-positive lung cancer is and how ALK gene rearrangements can cause cancer. This video was produced in 2020. For the latest treatment options, speak with your doctor.

Video transcript

Why ALK Biomarker Testing Matters

Biomarker testing matters for ALK‑positive lung cancer patients because it identifies the ALK rearrangement accurately, guides the use of highly effective targeted therapies, such as ALK inhibitors, and ensures no other actionable biomarkers are missed, all of which can lead to better survival and quality of life.

Biomarker testing looks for specific genetic changes in the tumor to help guide treatment. Testing includes DNA-based tests to identify changes in the genes themselves, and RNA-based tests to measure how those genes behave, giving your care team a fuller picture of your tumor makeup and available treatment options.

How IS ALK Testing Done?

Testing is usually done at diagnosis or when treatment changes. Your doctor will need to test your tumor through a tissue or blood (liquid) biopsy. There are several different types of tests that doctors use to look for changes, or biomarkers in your cells:

  • Fluorescence in Situ Hybridization, or FISH, analysis is a common genetic test. FISH analysis looks at changes in the chromosomes through tissue under a microscope.
  • Immunohistochemistry (IHC) looks for proteins in the cell under a microscope.
  • Next-generation sequencing (NGS), also called comprehensive biomarker testing, is when tissue from a patient's tumor (gathered from a biopsy) is placed in a machine that looks for many possible biomarkers at one time.
  • Reverse transcription polymerase chain reaction (RT-PCR) is a laboratory method used to make many copies of a specific genetic sequence for analysis.

Your doctor may perform several of these tests at the same time to help confirm results. Different biomarkers rely more heavily on certain tests.

Testing for ALK looks for ALK gene rearrangements (fusions). Doctors often use IHC to screen for ALK protein expression and then confirm results with FISH or NGS. NGS can also identify the specific ALK fusion variant. Liquid biopsy may be used when tissue is limited. 

Learn more about the different types of biomarker tests. 

In this video, Dr. Ross Camidge discusses the different biomarker tests used to determine whether a lung cancer is ALK-positive. This video was produced in 2020. For the latest treatment options, speak with your doctor.

Video transcript

Understanding Your ALK Test Results

An ALK-positive result means your cancer has an ALK rearrangement (fusion), a genetic change that can drive tumor growth and may make you eligible for targeted therapies or clinical trials designed for this biomarker.

You may have other biomarkers identified with different treatment options. When no actionable biomarkers are found, treatment usually focuses on immunotherapy, chemotherapy, or a combination of both. Doctors choose based on the cancer type, stage, and PD‑L1 level. Even without biomarkers, many effective treatment options exist, and your care team will tailor the plan to your situation.

Additional or repeat testing may be needed.

How ALK Results Influence Treatment

An ALK-positive result can help guide treatment decisions. Many patients with ALK-positive lung cancer are treated with targeted therapies called ALK inhibitors, which work to stop cancer growth by targeting the error in the ALK gene. For patients with stage IV lung cancer, ALK inhibitors will usually be the first choice of therapy. Other treatment options may also include surgery, radiation therapy, chemotherapy, immunotherapy, or participation in a clinical trial.

Treatment Options for ALK-Positive Lung Cancer

Learn more about ALK inhibitors, how treatment plans may change over time, and the options available for people living with ALK-positive lung cancer.
Explore ALK Treatment Options

Questions to Ask Your Doctor

Work with your doctor to discuss your goals and options each time you have to review and interpret test results to make a treatment decision. The three big questions to ask are:

  • What is the goal of this treatment?
  • What are the potential side effects?
  • What other options do I have?

Research is happening at a rapid pace, and your doctor should be up to date on the recommendations for your specific type of lung cancer. If you don’t feel comfortable with the answers you are receiving, do not hesitate to seek out a second opinion.

What You Can Do After an ALK Diagnosis

Someone with an ALK‑positive lung cancer diagnosis can take several empowering steps to stay ahead of their care. These are general medical information steps, not personal medical directives, and it’s important to work closely with a qualified healthcare professional for decisions about diagnosis or treatment. 

Even after an ALK fusion is found, it's important to ensure the tumor was tested with broad next‑generation sequencing (NGS). Why it matters: 

  • Confirms the ALK fusion type
  • Identifies any additional actionable mutations
  • Provides a baseline for future comparison

There are multiple ALK‑targeted therapies (alectinib, brigatinib, lorlatinib, etc.). Being proactive means understanding: 

  • Which drug you are on
  • Why it was chosen
  • What alternatives exist if resistance develops
  • Knowledge helps you participate confidently in treatment decisions

ALK inhibitors are generally well tolerated, but side effects can happen. Keeping a simple log helps your care team adjust treatment early and maintain quality of life.

ALK‑positive lung cancer has a higher likelihood of spreading to the brain. Proactive patients often discuss: 

  • MRI frequency
  • Whether their ALK inhibitor has strong brain penetration
  • Symptoms to watch for
  • Many ALK inhibitors (like alectinib and lorlatinib) work extremely well in the brain.

If the cancer grows or changes, repeat testing can identify resistance mutations. This guides the next treatment step, often switching to another ALK inhibitor that targets the new mutation.

ALK‑positive lung cancer research is fast‑moving. Trials may offer: 

  • Next‑generation ALK inhibitors
  • Combination therapies
  • Novel resistance‑targeting drugs

Ask questions, bring notes, and stay engaged. This helps ensure treatment decisions align with your goals and values so that you can make informed decisions.

Support and Patient Experiences

Whether you're newly diagnosed or navigating treatment, support resources and patient experiences can help you better understand your options and connect with others.

Connect with Support Resources

It is important to work closely with your physicians to help monitor your medication side effects. Ask about connecting with a supportive/palliative care doctor at the beginning of your treatment to help ensure your side effects are well managed.

Hear From Other Patients

In this video, Lisa shares her advice for people who have recently been diagnosed with ALK-positive lung cancer, including the importance of support, education, and hope.

ALK-positive lung cancer patient, Lisa, shares what she would tell a newly diagnosed ALK-lung cancer patient.

Video transcript

Lung cancer research can move at a rapid pace. Always speak with your doctor about the most up-to-date treatment guidelines.

Medically reviewed by: Jorge Gomez, MD
Last reviewed: June 2026 

Page last updated: August 13, 2026

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