In an interview with _Pharmacy Times®,_ Megan Tesch MD, MPH**,** breast medical oncologist from the Dana-Farber Cancer Institute, shared that higher levels of certain tumor-infiltrating lymphocytes (TILs) subtypes in young breast cancer patients were associated with better pathologic complete response rates to neoadjuvant chemotherapy. This suggests TIL assessment could help predict which young patients are likely to benefit most from neoadjuvant chemo. Tesch noted that further exploration is warranted to validate these findings and investigate how TIL profiles could guide personalized treatment strategies, such as the use of immunotherapies, in this patient population.
**Pharmacy Times**
How do TIL levels correlate with response to neoadjuvant chemotherapy in young breast cancer patients?
**Megan Tesch MD, MPH**
In our study, which was of patients who are age 40 years or younger at time of breast cancer diagnosis, we saw that increased levels of stromal T regulatory cells and all intertumoral TIL subtypes were associated with a greater odd of achieving a pathologic complete response after neoadjuvant chemotherapy for stage I to III breast cancer.
**Pharmacy Times**
Can TIL assessment be used to predict which young patients will benefit most from neoadjuvant chemotherapy?
**Tesch**
Our study findings are interesting. They do require further validation in a larger sample, but there does seem to be a signal there that having higher levels of TILs in your tumor tissue pretreatment would correlate with having a better response to neoadjuvant chemotherapy.
**Pharmacy Times**
What are the potential implications of TIL assessment for personalized treatment strategies in young breast cancer patients?
**Tesch**
The idea would be with further validation that by assessing the pretreatment tumor microenvironment of young patient’s breast tumors would help us in determining what kind of response they're going to have from neoadjuvant chemotherapy. It might help identify subgroups where there's predicted to be a poor response to neoadjuvant chemotherapy, where they might benefit from additional immunomodulatory strategies to bolster their immune response, versus patients where they'll have an excellent response, regardless of whether they receive immune checkpoint inhibitors or other sorts of immunotherapy strategies.
**Pharmacy Times**
Is there anything you would like to add?
**Tesch**
I guess I'll just say that in this study, we did see some interesting associations between certain clinical pathologic characteristics of young patients with TIL levels. For example, patients who had recent pregnancy, or those with germline BRCA 1 mutation. These are really features that are quite unique to a young patient population, and would indicate, potentially, that there are features that make young patients perhaps have more immunogenic tumors. I think this is something that should be further explored as well when we try to look at using immune biomarkers in this patient population.