Finally, we are in the realm of immunotherapy—which has taken the oncology world by storm—and determining other predictors for response to immunotherapy. However, other than tumor-infiltrating lymphocytes, we are not in an era where we can even measure subsets of T cells.
All of these things are coming down the pike, and I do think that, over the next decade or so, breast cancer will be managed more like a chronic disease.
Do you see blood-based tests becoming the standard approach?
Yes, I do, but the validations do need to get done. With liquid biopsies and blood-based tests, especially now that you can sequence a single cell, you can actually look at the plasma and see the tumor DNA—the cancer DNA that’s being shed into the plasma and exosomes in the blood.
All of these fantastic tools that we now have just adds to a more complete understanding of breast cancer and who needs therapy, who does not need therapy, and what therapy to give. It’s all just very exciting.
Are there ongoing studies related to this that will be important going forward?
There are a few studies that have been presented regarding what kind of therapies will provide benefit if you have this ER mutation. It’s going to be different depending on the subset of cancer. Molecular testing will aid in these different subsets in different ways.
What role do you envision for immunotherapy in the future?
Most of the effort has been in TNBC, and rightly so, because it has the most aberrant tumor with the highest mutational landscape. Approximately 15% of TNBCs respond to immune checkpoints. So, how do we make this better? Can we select who will benefit from immune checkpoints? Is it going to be as simple as immunohistochemistry testing for PD-1/PD-L1? I don't think so. Is it just going to be the mutational landscape, or are there new tests? Those studies are being done.