Programmed cell death protein 1 is a marker for neoadjuvant chemotherapy response in triple-negative breast cancer.

In this study, we observed that chemotherapy significantly increases stromal tumor-infiltrating lymphocytes, CD8 T cells, as well as CD8/FoxP3 ratio. Most importantly, programmed cell death protein 1 expression before neoadjuvant chemotherapy positively correlates with pathological response suggesting the use of programmed cell death protein 1 as a prognostic marker before neoadjuvant chemotherapy.