Video: What is a Liquid Biopsy? | Helpline Questions

Helpline Questions | Transcription

Hi, I'm Dr. Scholz. 

A common question we get at the PCRI is, "How does a liquid biopsy work?" 

Well, when we hear biopsy, we think of needles going in and removing tissue for genetic or pathologic analysis. A liquid biopsy is evaluating DNA floating in the bloodstream. And DNA from tumor cells is released into the bloodstream and can be extracted with a blood test and then analyzed for genetic analysis. So a liquid biopsy is really only for genetic analysis. They can't do pathologic analysis; you can't get a Gleason score from a liquid biopsy, but you can look for mutations. And this is a common process that's done in people with very advanced cancers and there's an attempt to determine, "Is there some specific mutation that would lend or point toward a type of therapy that could be effective in that specific individual?" So liquid biopsies are nothing more than DNA analysis of cancer DNA that's being released from cancer cells into the bloodstream—that's just part of the process of what happens with cancer cells—and that DNA then is used for genetic analysis to determine potential weak spots in the cancer cells that can be attacked with specific therapies.