KRAS and Lung Cancer

What is the KRAS mutation?

An error in the KRAS gene is one type of lung cancer biomarker. It is called KRAS because it was first identified as causing cancer in Kirsten rat sarcoma virus. There are other types of RAS mutations, but targeted treatment is currently only available for KRAS in patients with lung cancer, and specifically for one type of KRAS mutation called a G12C mutation. The KRAS gene normally acts as a communication hub for signals that lead to cell growth. When a mutation occurs, KRAS send too many signals, causing uncontrolled cell growth and leading to cancer.

Who is most likely to have a KRAS mutation?

KRAS gene mutations are more commonly found in people who currently or have smoked in the past. However, KRAS mutations can also occur in patients with diverse backgrounds. About 25% of all patients with lung cancer have some form of KRAS mutation.

How do you know if you have a KRAS mutation?

There are several ways to detect KRAS mutations. One way is through next-generation sequencing (NGS), also called comprehensive biomarker testing. For this type of testing, tissue from a patient’s tumor (gathered from a biopsy) is analyzed to look for many possible biomarkers (including mutations) in many cancer-related genes simultaneously. In some situations, a patient may not be able to have the biopsy needed to perform NGS testing, so a liquid biopsy may be recommended instead. A liquid biopsy can look for certain biomarkers in a patient’s blood. Talk to your doctor to make sure one of these tests was performed.

Learn more about the different types of biomarker tests.

Are there different types of KRAS mutations?

There are several types of KRAS mutations. About half of patients with lung cancer who have a KRAS mutation have a KRAS G12C mutation. The other types of KRAS mutations show up in the other half of patients. KRAS mutations can also occur when other genetic mutations, like STK11, which are seen in about 10% of lung adenocarcinomas. 

What is the course of treatment like for someone with a KRAS mutation?

Currently, the standard first-line therapy for a patient with KRAS-positive lung cancer depends on the stage of their cancer. Treatment may include surgery, radiation, chemotherapy, immunotherapy or a combination.

For patients with KRAS G12C, there are currently two approved targeted therapy pills, also called KRAS inhibitors. If a patient’s cancer stops responding to chemotherapy or immunotherapy, or a combination both, targeted drugs sotorasib (Lumakras) or adagrasib (Krazati) may be recommended.

There are many other medicines being studied in clinical trials to treat KRAS-positive lung cancer. All patients with lung cancer should discuss clinical trials with their doctor.

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

1. What is the goal of this treatment?
2. What are the potential side effects?
3. 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.