A "Liquid Biopsy" for Lung Cancer

There are several known possible genetic mutations in non-small cell lung cancer (NSCLC), the most common form of lung cancer. Depending on which of several mutations it is, the cancer cells will respond differently to different treatments. The problem is that in the past the only way to tell which type of genetic mutation was present, and hence which treatment would work best, was a biopsy, which is invasive and often painful. A biopsy is certainly worth doing, of course, if it's required for adequate diagnosis and treatment, but not if there were an easier or better way.

Now scientists may have found that easier way. When cancer cells die (or when any cells die, for that matter), their DNA is spilled into the blood. By testing a sample of the patient's blood for the various possible genetic mutations found in NSCLC cells, it should be possible to identify the specific genetic mutation present, and thus to know which of several treatment options is likely to work best.

That's precisely what research conducted at the Dana Farber Cancer Center in Boston has found. The researchers have identified two key genes found in NSCLC cells using just a single test tube of blood. Technically known as plasma genotyping, the new test is also referred to as a "liquid biopsy" because it serves the same function as a traditional tissue-based biopsy, only using a liquid (blood).

In addition to helping physicians determine which of several treatment options to offer the patient, the liquid biopsy can also be used to determine how well the patient is responding to the treatment. If the cancer treatment is working, for example, the unique genes found in NSCLC cells should begin to disappear from future liquid biopsies.