People's responses to anticancer drugs vary. Not everyone who is given a particular drug will have a good response to that drug. This is true for chemotherapy and targeted therapies.
The KRAS protein acts as an on-off switch in a 'grow and divide' process that is started by the growth factor EGF when it attaches to its receptor (the EGFR) on the surface of cells. This 'grow and divide' process may be out of control in colorectal cancer cells, making the cells divide many times, eventually forming a tumor. You can find more about this process by following the link at the end of this section to 'About KRAS'
Drugs that block the EGFR can slow down this process when it is out of control, but these drugs are effective only if the KRAS on-off switch is working properly. The KRAS test finds out if the KRAS gene is normal (also called wild-type) or abnormal (also called mutant).
Health organizations that license drugs for use in patients have decided that anti-EGFR drugs should only be given to patients with metastatic colorectal cancer when the KRAS gene in their tumor is normal, because these drugs are only effective when normal KRAS is present. When the abnormal KRAS gene is present, anti-EGFR targeted therapies should not be used.
If your KRAS test result is ''normal', your doctor will be able to add anti-EGFR targeted treatment to the chemotherapy that you will be given for your metastatic colorectal cancer, if it is considered appropriate. If your KRAS test result is ''abnormal', your doctor may consider other targeted treatments that can be added to the chemotherapy. You can learn more about these treatment options by following the links below.
To find out more about treatment options when the KRAS test indicates that KRAS is normal, go to KRAS is normal in the tumor.
To find out more about treatment options when the KRAS test indicates that KRAS is abnormal, go to KRAS is abnormal in the tumor.
To find out more about treatment options for metastatic colorectal cancer, go to What are the treatment options for metastatic colorectal cancer?
To find out more about the KRAS gene and protein, go to About KRAS