Genomics Thread #6

Let's talk about liquid biopsies...

1/ A liquid biopsy is usually a blood-based test that can detect cancer.

How?

By detecting either CTC (circulating tumor cells) or ctDNA (circulating tumor DNA). In some studies, ctDNA has been shown to have 100x the concentration as CTC though.

2/ So why is this important?

Well, the standard of care is tissue biopsies. Doctors lop off a piece of the potentially cancerous area (a chunk of your lung for lung cancer for instance) to verify if cancer exists.

However, tissue biopsies are inferior in a few ways...

3/

1. For one, there are more complications. Lung biopsies had a 19% complication rate.

2. They are also expensive, costing nearly $15,000 for each one.

3. They leave a scar and require a surgery

4. It takes a while to get the results

5. Not a lot of tissue can be retrieved

4/ On the other hand, liquid biopsies only require a vial of blood. These genetic tests can profile dozens of genes and determine whether a tumor is malignant.

The main players that already have an approved test are Guardant Health and Foundation Medicine (owned by Roche).