Lung cancer is an aggressive type of cancer that begins in the lungs but may spread to other areas of the body.

With an estimated 30% 5-year relative survival rate, lung cancer is among the deadliest forms of cancer and is also the third most common of all cancers in the United States.

While knowing the symptoms of lung cancer more broadly can help you obtain a timely diagnosis, there are other factors to consider, too. These include genetic mutations that may affect your risk and treatment options, such as the KRAS mutation.

Learn more about the KRAS mutation, including your risk of carrying it and what you can do if a doctor determines you may have it.

The KRAS mutation refers to a type of error or genetic biomarker that may be present in some people who develop non-small cell lung cancer (NSCLC) — which is considered the most common type of lung cancer, making up between 80% and 85% of all cases.

Pronounced as “K-raz,” this genetic mutation may increase lung cancer risk and influence treatment options for those with lung cancer.

Having a KRAS mutation means that there may be a problem within the proteins of the KRAS gene. While KRAS normally helps with cell growth, having a mutation can tell your cells to grow more than they need to. This overgrowth can lead to cancerous tumors.

It’s important to note that this gene mutation can also be seen in pancreatic and colorectal cancers.

Are there different types of KRAS mutations?

There are several types of KRAS mutations, including:

  • G12A
  • G12C
  • G12D
  • G12S
  • G12R
  • G12V

In a 2017 study conducted at a pulmonary hospital in Shanghai, 218 people with NSCLC were found to have KRAS mutations. The three most common were G12C (32.1%), G12D (23.4%), and G12V (21.1%). The other mutations were found in about 20% of people with NSCLC.

Having a KRAS mutation is common — in fact, it’s estimated that between 20% and 25% of people with lung cancer have it.

The American Lung Association notes that KRAS mutations are most common in current or former smokers and those of Western European descent.

But a 2021 review suggests that it is possible to develop KRAS-positive lung cancer as a nonsmoker. The estimated rates of KRAS-positive lung cancer are 30% in smokers and 11% in nonsmokers.

The only way to confirm KRAS mutation is to undergo genetic testing, which looks for mutations in the KRAS gene on cancer cells.

This may be done in two ways:

  • Next-generation sequencing (NGS): Considered the best way to test for KRAS, this method involves taking a biopsy of the cancerous tumor and running it through a specialized machine that detects multiple gene mutations in cancer cells at once.
  • Liquid biopsy: In cases where a traditional needle-based biopsy needed for NGS can’t be performed, a liquid biopsy may be recommended to test for KRAS mutation. This involves looking for a more limited number of gene mutations in cancer cells via blood testing.

The initial treatments for KRAS and non-KRAS lung cancer are the same and may include a combination of:

  • chemotherapy
  • immunotherapy
  • radiation therapy
  • surgery, which may involve removing a portion of the lung(s)

But according to a 2021 clinical review, KRAS mutations may not respond well to typical cancer treatments after their initial use. This is where targeted therapies may help.

If you do have a KRAS mutation, certain targeted therapies called KRAS inhibitors may be recommended. This helps prevent the KRAS gene from promoting cell overgrowth.

Other targeted therapies may be considered for additional KRAS subtypes, with new potential drugs being tested in clinical trials.

According to the National Cancer Institute (NCI), there were an estimated 236,740 new lung and bronchus cancer cases and 130,180 estimated deaths due to this type of cancer.

While testing for the presence of KRAS mutation is important in determining whether you need targeted therapies, the overall survival rate depends on the stage of your cancer. Additionally, your individual response to KRAS inhibitors may also play a role in your prognosis.

The sooner lung cancer is caught, the better the chances of a higher 5-year relative survival rate. This is because early cancers tend to be in lower stages.

The lower the stage, the more likely the cancer is localized, meaning that it hasn’t spread.

KRAS mutations are common features in NCSLCs. If you have been diagnosed with this type of cancer, consider talking with a doctor about testing for a KRAS gene mutation. This can help determine better treatment options to improve your overall outlook and survival rate.

Additionally, whether you have KRAS-positive lung cancer or not, it’s crucial to speak with a doctor as soon as you experience possible symptoms of this type of cancer. These can include chronic cough, wheezing, chest pain, and coughing up blood.

While KRAS mutations may be difficult to treat, targeted therapies may help block the underlying mechanisms that lead to future tumor growth. Additionally, new therapies are continuously being studied for multiple KRAS subtypes.