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KRAS biomarker and colorectal cancer

female researcher with a microscope
abnormal pink cells

What is a KRAS biomarker?

KRAS is a member of the RAS family of genes that include NRAS and HRAS.

A normal KRAS gene teams up with a group of proteins as an “on/off” switch to monitor cell growth. An abnormal mutation in the KRAS gene happens early in the development of cancer.

This abnormality is known as a driver mutation because it causes the switch to be locked in the “on” position and drives uncontrolled cell growth, leading a tumor to form.

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How common are KRAS mutations?

Approximately 40-45 percent of colorectal cancer patients have a KRAS mutation in their tumor.

A KRAS mutation is not hereditary (a germline mutation) and will not be passed from one generation to another in a family.

All KRAS mutations happen randomly and are somatic or non-hereditary mutations. The most common KRAS mutations are G12V, G12D, G14D, G12C, and G12A.

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Who should have KRAS biomarker testing?

Patients with stage IV (metastatic) colorectal cancer should be tested for KRAS mutations.

KRAS status must be determined prior to the start of any EGFR-inhibitors, as a positive KRAS mutation is a predictor of a poor response to these drugs.

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What treatment options are available?

Patients with mutated or unknown KRAS status should receive chemotherapy including FOLFOX, CAPOX, or FOLFIRI with or without bevacizumab.

Currently, there are no specific anti-KRAS therapies but there are ongoing clinical trials looking at potential KRAS inhibitors.

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What are potential side effects from treatment?

Every treatment has the potential to cause some side effects. Some people may be more sensitive than others to a particular drug. The response to a specific treatment also depends on your other treatments (for example, radiation) and medications. Contact your doctor immediately if you are experiencing severe symptoms.

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