Phillip Koo:

There’s a question about liquid biopsies. We hear so many different terms of liquid biopsy this, CT circulating tumor cells. It's confusing. Can you sort of help us understand what is liquid and what is solid? What… yeah.

Zachary Klaassen:

Yeah, so it's a huge topic right now, particularly in bladder cancer, where we're seeing some really interesting data for being able to track patients and how they're doing with ctDNA. Basically, what it is, is a blood test that basically looks at the amount of tumor content that has… that's floating in the blood, essentially. That's the easiest way to put it, I guess.

It's still somewhat… I don't want to say new in prostate cancer, but figuring out how to utilize it. I think where it's helpful is, if you have a new diagnosis of metastatic prostate cancer, or you've progressed and your physician wants to know, has there been genetic changes?

If a spot is not amenable to a biopsy, such as it's in a difficult location in the bone or it's not easy to get to in the liver or the lung. We're seeing that we're able to do some of that… some of that genetic testing on the ctDNA, and there's a pretty good correlation between what's going on in that tumor itself in the body and what's floating in the blood. That's a… we could do a one-hour seminar on ctDNA today, though.