ALK

ALK+ lung cancer

About ALK+ NSCLC

If you have been told that you have ALK+ NSCLC, you might be wondering what this means.

Firstly, NSCLC stands for 'non-small cell lung cancer' – you can learn more about what this is here. About 85% of people with lung cancer have NSCLC.1

To understand what ALK+ means, we need to learn a bit more about 'DNA'.

Your body is made up of trillions of tiny building blocks called cells. Inside each cell is DNA. DNA is like a set of instructions that tell your cells what to do. They tell the cell to make certain things, when to grow or multiply, when to move around, and even when it is time to die.2

Normally your DNA helps keep your cells in a careful balance,3 so that they are multiplying and dying at a similar speed. But sometimes something goes wrong, and the DNA changes. This can cause cells to grow too fast and eventually make a tumour.2

ALK+ means that you have a change in a small part of your DNA (the small part is called a ‘gene’) that makes a protein called ALK (or 'anaplastic lymphoma kinase'). This protein is responsible for a few different things, including telling cells to grow and multiply, and move around.4,5

ALK doesn’t exist in healthy lungs – your cells would normally ignore that bit of information in your DNA. But in ALK+ NSCLC, the change in the gene means that your lung cells start making the ALK protein. When this happens, your cells start to grow and multiply out of control, and eventually they build up and become tumours.6–9


You can learn more about how changes to your ALK gene can cause NSCLC with the diagram below:

In a cell from ALKNSCLC, the gene for ALK somehow becomes changed.

Because the gene has changed, it becomes known as ALK+ (ALK-positive).

The changed ALK+ gene contains altered instructions, which create an altered version of the ALK receptor.
Once it’s sat on the surface, the altered ALK receptor cannot control all the messages coming in.
The cells with the ALK+ receptor end up being bombarded with messages telling the cells to grow and multiply, forming tumours, which may begin to spread around the body.
Only about 5% of people with NSCLC (1 in 20) have a change in their ALK gene.1 We don’t know exactly what causes the DNA to change in somebody with ALK+ NSCLC, but you can learn more about some risk factors for lung cancer further down this page.

People who have ALK+ NSCLC

People who are diagnosed with ALK+ NSCLC tend to be:
  • Younger than a lot of other people diagnosed with cancer10–12
    About a third of people with ALK+ NSCLC are diagnosed before they are 40, and about half by the time they are 50. In comparison, most people with lung cancer are usually diagnosed around the age of 70
  • Never-smokers, or light smokers10,11,13,14
    Many people who are diagnosed with ALK+ NSCLC have only lightly smoked, or never even smoked at all

Risk factors for developing ALK+ NSCLC

Right now, we don’t know exactly why some people develop a change in their ALK gene.

Although smoking and being exposed to second-hand smoke are some of the most well-known causes of lung cancer,15 people who develop ALK+ NSCLC have often never smoked, or may have only lightly smoked, in the past.5,16

Developing lung cancer when you have little or no smoking history can be extremely frustrating, and you might find yourself looking for answers as to why you have developed lung cancer at all.

There are a number of other factors (summarised below) that are thought to be associated with the development of NSCLCs. However, it’s important to note that for some people, there may be no obvious cause as to why they have developed ALK+ NSCLC.

Exposure to inhaled or ingested substances such as:
  • Asbestos17
  • Arsenic17
  • Non-tobacco smoke (e.g. burning buildings and wildfires, which may contain traces of metals and other carcinogenic substances)17
  • Diesel exhaust17
  • Metals such as chromium, beryllium, and nickel (you might be exposed to these if you work with car engines, or around smelting or welding, for example)17
  • Atmospheric pollutants18
Radiation exposure from:
  • X-rays, CT scans19
  • Radiotherapy to the chest area20
  • Radon exposure21
  • Exposure to radioactive fallout22
Family history/genetics
  • Although inheritance is not guaranteed, people with a family history of lung cancer are more likely to develop it than people without22,23
HIV infection
  • People with HIV are up to three times more likely to develop lung cancer than those without the infection24,25

How will my doctor know if I have a change in my ALK gene?

Getting an accurate diagnosis is important, so your doctor will make sure you have various tests to find out as much about your cancer as possible. That way, you and they can work together to create the best possible treatment plan for you.

Tests to see if you have a change in your ALK gene will include a biopsy – you can learn more about these here.

You can learn more about how changes to your genes can cause cancer here.


Does having a change in my ALK gene affect my prognosis?

When thinking about what it means to have ALK+ NSCLC, many people wonder what their prognosis is. But cancer is a highly complex disease that can be affected by lots of different factors, so it’s hard for a doctor to give anybody an exact amount of time. These factors can include:

  • Your age 
  • Your sex
  • Your race/ethnicity 
  • Where you live and work 
  • The type of work you do 
  • Your diet 
  • Your weight 
  • If you’ve ever smoked/how much alcohol you drink
  • Your family history of illnesses 

It's worth being aware that ALK+ NSCLC is considered more aggressive than some other forms of NSCLC26 – nine out of 10 people are diagnosed after the cancer has already spread to other parts of their body (called ‘metastasis’, or ‘advanced cancer’).27,28 With regular chemotherapy, about half of people with advanced ALK+ NSCLC pass away about 2 years after their diagnosis.29

However, research has led to the discovery of modern treatments called ‘ALK inhibitors’, which are specifically designed to treat ALK+ NSCLC.30,31

These ALK inhibitors have helped increase the time that somebody can live with ALK+ NSCLC. In 2019, a clinical trial in 110 people with advanced, stage 4 ALK+ NSCLC was published. It found that with treatment, half of the patients were still alive almost 7 years later.32

Click on one of the options below to learn more 


ALKAnaplastic lymphoma kinase
DNADeoxyribonucleic acid
NSCLCNon-small cell lung cancer

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