Investigating the Correlation between Immune Infiltrate and Treatment Response in Triple Negative Breast Cancer Patients

Triple-negative breast cancers (TNBC) lack progesterone, estrogen, and human epidermal growth factor receptors. Consequently, traditional hormone therapies are ineffective against TNBC resulting in fewer treatment options compared to other types of breast cancer. However, immunotherapy has emerged as an effective treatment for TNBC due to higher expression of PD-L1 and more tumor infiltrating lymphocytes (TILs) in TNBCs compared to other types of breast tumors. Here, we aim to (1) characterize the immune infiltrate of TNBC patient tumor biopsies, and (2) assess how patients respond to immune checkpoint blockade (ICB) therapy based on immune infiltration of tumors. We will collect tumor biopsies from treatment-naive females with TNBC, and conduct imaging mass cytometry to identify infiltrating immune cells, including lymphoid and myeloid lineage cells. Patients will be subject to immune checkpoint blockade therapy and receive monthly checkups, where mammograms will be performed to assess structural changes of the cancer to determine the effectiveness of the treatment over time. We predict the treatment will be more effective in patients with high levels of TILs and myeloid-derivedsuppressor cells (MDSCs). The results of this study may confirm that a higher presence of TILs and MDSCs generally correlates to a better response to ICB therapy.