Biomarker Testing

Lung cancer can often feel like moving to a new country. You don’t speak the language, you don’t know the habits or customs, and you feel lost.

That’s what one person with lung cancer said about her diagnosis. These and similar feelings can be all too common. And that’s why we’ve provided some information about some lung cancer topics: lung cancer mutations, their identification, and treatments.


MUTATIONS

Every cell in your body has your DNA. DNA contains your genes, the recipe book for what makes you who you are. For example, your DNA determines your hair color, or your height, or whether you like sweets or if you prefer salty foods.

As we’ve learned more about genes, we’ve discovered several types of mutations. A genetic mutation is a change to the make up of the gene. Some mutations are harmless. For example, scientists believe blue eye color stems from a common ancestor with a genetic mutation. However, some mutations cause faulty proteins to be grown, increasing the risk of certain diseases like cancer. Here, we are going to dig deeper to understand more about mutations that can increase the risk of lung cancer.

Not all lung cancers are the same. There are several different kinds of mutations. Mutations like epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), and Reactive Oxygen Species 1 (ROS1) have been known to increase the risk of either creating or allowing the spread of cancerous cells. These types of mutations serve as biomarkers, alerting medical professionals to a particular form of the disease.

There are several tests doctors can run to determine whether your lung cancer is caused by a specific mutation. Testing for mutations is becoming the accepted standard of care, so if you haven’t been tested, ask your doctor if there is a reason why. Testing can be a simple blood test, or it can be more involved, such as with a tissue biopsy. There are other options, as well. Testing is really important because it can guide additional treatment options that are targeted at specific types of lung cancer.

Some examples of treatment types include targeted therapy products, Immuno-oncology products, chemotherapy, or experimental medicine in clinical trials.

Chemotherapy is a combination of medicines that act to kill cancer cells by stopping cell division. TKIs, along with BRAF and MEK inhibitors, are medications that target a cell’s receptors in an effort to prevent, or inhibit, the cell from growing or spreading. Immuno-oncology products strengthen the body’s immune system to better fight a specific type of cancer. Clinical trials are research studies for investigational treatments that have not officially been approved by governing health organizations. Your doctor will tell you more about clinical trials if those become appropriate options for you, but we will focus the rest of our discussion on therapies that target specific mutations.

Sure. Let’s look at the EGFR mutation mentioned above.

Cells, including cancer cells, communicate with each other and their surroundings through signals. On the surface of the cell is a protein called ‘EGFR’. EGFR acts like a switch that tells the cell when to grow and divide to make new cells.

If a mutation occurs, the EGFR “switch” gets stuck in an "on" position. The mutated EGFR is not able to stop sending signals to the cell to grow. This causes the cells to divide in an uncontrolled manner, leading to cancer.

The c-MET mutation works in a very similar way, though with the hepatocyte growth factor (HGF) instead of the epidermal growth factor (EGFR).


PROGRESSION

Eventually, after initial treatment, cancer cells can develop alternative resistance mechanisms, testing can be reinitiated, and alternative treatments will be assessed by your healthcare professional to the treatment. This is most often called progression.

Cancer cells can become resistant to treatment, meaning that the treatment can no longer block the growth of the cancer cells. As the treatment becomes less effective, the cancer starts growing and spreading again – this is called progression. One way in which cancer cells become resistant is by developing another gene mutation or a change in the gene that was targeted by the treatment. For patients with ALK mutation, resistance to treatment is also often due to the development of secondary ALK mutations. For patients with an EGFR mutation, one mutation that people often have at progression is the EGFR T790M mutation. When this happens, the receptor/protein in the cancer cells becomes stuck in the "on" position like it was when the cancer first started growing. Progression, may initially seem scary, but it can guide the next treatment options. Knowing why your cancer has become resistant to your first treatment, will help your doctor and you decide what treatment you could receive next.

It’s important to alert your doctor if you experience new symptoms or if some of the symptoms that you may have experienced before the initial treatment return. These symptoms may include chest pain, shortness of breath, headache, continuous coughing, difficulty eating, hoarseness or wheezing.

A symptoms log is a good way to track changes in how you’re feeling from day to day, and will help you stay organized for your checkups.


TESTING

There are several tests that can be performed to identify whether the cancer cells have changed. This information will allow your healthcare team to develop a treatment plan that is best for you.

Below are some of the tests your doctor could recommend to plan a course of action.

Mutation Analysis

To test for the mutation, a liquid biopsy and/or a tissue biopsy can be performed.

Liquid Biopsy

A liquid biopsy is performed by taking a sample of blood to look for pieces of DNA from cancer cells that might be present in the bloodstream. These cells or pieces of DNA can be used to test for the presence of mutations.

A liquid biopsy is often used as a minimally invasive preliminary test. Nevertheless, if the result of this test is negative or if it is unclear if a mutation is present, then a tissue biopsy may be recommended.

Tissue Biopsy

A tissue biopsy is performed by taking a sample of cells or tissue directly from the cancer. These cells or tissue can be used to test for the presence of mutations. Depending on how the sample is collected, the biopsy may be performed in your doctor’s office, at the hospital, or surgical center. It’s not always possible to perform a tissue biopsy depending on a number of factors including your health status.

Mutations and Biomarkers


How do I ask my doctor about testing?

Asking your doctor about mutations and progression can be stressful, but with the results of these tests, your doctor can find the treatment that is right for you.

You can start with simple questions, like these:

  • Has my cancer been tested for a mutation?
  • What mutations was my cancer tested for?
  • What were the results of the testing?
  • Are there other tests I should have done, so that we know all we can about my cancer?
  • How are those tests performed?
  • How will the outcome of the tests change my current treatment options?
  • What if the tests are negative? What will we do then?

If you’re feeling nervous about asking these questions, write them down on a notepad or journal and be sure to have it with you when you go to your appointment. Call ahead and let the doctor or nurse know that you have some questions and that you may need more time than normal.

Being prepared is easier if you’ve talked with your doctor about planning for progression and if you’ve been documenting your symptoms during treatment. You will be able to track any changes, giving you a better chance of catching treatment resistance early.

If you feel changes, don’t be afraid to tell your doctor and discuss with your doctor your current treatment plan and what future treatments may be an option. They’re on your team!