150P Dysregulation of immune checkpoint proteins in newly-diagnosed early breast cancer patients

Checkpoint proteins regulate the immune system. Breast cancer (BC) cells can up-regulate or down-regulate these proteins to evade anti-tumor immune responses. Soluble forms of immune checkpoint molecules (ICMs) can be measured in human plasma. The study aimed to measure the systemic levels of a series of positive and negative ICMs at diagnosis, post-neo-adjuvant chemotherapy (NAC) and post-surgery in newly- diagnosed BC patients (pts) relative to those of a healthy control group.