You are now leaving lvng.ca.

You have selected a link that will take you to a site maintained by a third party who is solely responsible for its contents.

We encourage you to read the privacy policy of every website you visit.

Click 'Cancel' to return to lvng.ca or 'OK' to proceed.

You are now leaving lvng.ca.

You have selected a link that will take you to a site maintained by a third party who is solely responsible for its contents.

We encourage you to read the privacy policy of every website you visit.

Click 'Cancel' to return to lvng.ca or 'OK' to proceed.

You are now leaving lvng.ca.

You have selected a link that will take you to a site maintained by a third party who is solely responsible for its contents.

We encourage you to read the privacy policy of every website you visit.

Click 'Cancel' to return to lvng.ca or 'OK' to proceed.

You are now leaving lvng.ca.

You have selected a link that will take you to a site maintained by a third party who is solely responsible for its contents.

We encourage you to read the privacy policy of every website you visit.

Click 'Cancel' to return to lvng.ca or 'OK' to proceed.

You are now leaving lvng.ca.

You have selected a link that will take you to a site maintained by a third party who is solely responsible for its contents.

We encourage you to read the privacy policy of every website you visit.

Click 'Cancel' to return to lvng.ca or 'OK' to proceed.

You are now leaving lvng.ca.

You have selected a link that will take you to a site maintained by a third party who is solely responsible for its contents.

We encourage you to read the privacy policy of every website you visit.

Click 'Cancel' to return to lvng.ca or 'OK' to proceed.

You are now leaving lvng.ca.

You have selected a link that will take you to a site maintained by a third party who is solely responsible for its contents.

We encourage you to read the privacy policy of every website you visit.

Click 'Cancel' to return to lvng.ca or 'OK' to proceed.

How Is Mutation Testing Done?

The main types of mutation testing are immunohistochemistry and molecular testing. The type of testing can vary with the mutation in question. Molecular testing is done using samples of tissue or plasma (i.e., blood) from a biopsy.

Collecting enough tissue during a biopsy is important for both immunohistochemistry and molecular testing. CT scans or ultrasounds may be used to "guide" the biopsy for lung cancer so that the samples are taken from the right spot.

Immunohistochemistry

Immunohistochemistry is a laboratory test that uses antibodies to test for certain markers (or antigens) in a sample of tissue. The antibodies are usually linked to an enzyme or a fluorescent dye. When the antibodies attach on to the antigen in the tissue sample, the enzyme or dye is activated. With this, the antigen can be seen under a microscope.

Immunohistochemistry tests help identify the type and subtype of lung cancer. For example, immunohistochemistry staining can identify mutations in the ALK (anaplastic lymphoma kinase) gene that controls the growth of cells.

Molecular testing

Molecular tissue tests evaluate changes (mutations) in the genes of lung cancer cells. These mutations affect the choice of treatment given because certain drugs are designed to target cancer cells with these mutations.

For example, EGFR (epidermal growth factor receptor) is a protein found on the surface of cells. This protein helps cells grow. Mutations in the EGFR gene can cause a more than normal amount of EGFR in some types of lung cancer and may lead to spread of the cancer.

Tissue biopsy

A biopsy involves removing a sample of tissue or tumour from the body and looking at it under a microscope to check for cancer cells.

Tissue biopsies can be done to help diagnose your cancer. As well, they may also be done if your cancer progresses to identify if any additional or new mutations have occurred.

Biopsies can also be done with plasma (i.e., blood) rather than tissue samples. For more information on plasma biopsy, see the section "Plasma biopsy".

Tissue samples for a biopsy can be taken from almost any part of the body. Tissue sampling for a biopsy can be done by needle, scrape or brush, surgically and endoscopically (an endoscopy is done with a flexible or rigid tube with a light and lens on the end that goes into the body to help the doctor find the cancer). The type of biopsy chosen depends on the area of the body and the type of cancer suspected.

Plasma biopsy (ctDNA)

Plasma biopsy (also be called "liquid biopsy") can be used at diagnosis and if the cancer progresses (spreads).

Like tissue biopsy, plasma biopsy helps identify specific mutations in the cancer cell genes; however, it is less invasive and is requires less time. This type of biopsy is possible because the DNA (genetic material) of tumour cells can be isolated from a plasma sample. The circulating-free tumor DNA may be referred to as ctDNA or cfDNA. For example, plasma biopsy is another option used to check if the patient has the EGFR T790M mutation. It is now available in Canada and may be considered as an option to check for this mutation. Plasma biopsy (ctDNA) has been found to have a sensitivity level of approximately 60% in detecting the EGFR T790M mutation. This means plasma biopsy will give the same results as a tissue biopsy 60% of the time (sensitivity can also be referred to as "positive percent agreement"). However, if the plasma biopsy is negative, it is important to confirm the test result with a follow-up tissue biopsy as this test is more sensitive.