Abstract PS17-36: Dysregulation of soluble immune checkpoint proteins in newly - diagnosed early breast cancer patients

Background: Checkpoint proteins regulate the immune system. Breast cancer (BC) cells exploit the up-regulation or down-regulation of these proteins to evade anti-tumor immune responses. Soluble forms of immune checkpoint molecules (ICM) can be measured in human plasma. However, their biological and clinical significance remains mostly unknown. The aim of the present analysis was to measure the levels of pre-treatment ICM in newly diagnosed BC patients (pts) and compare them to healthy controls. Method: Soluble forms of ICM, as well as cytokines and chemokines, were measured using Multiplex® bead array and ELISA technologies. Plasma samples from 98 BC pts and 45 healthy controls were analyzed for each protein. Data was prospectively obtained. Measured levels were compared between BC pts and healthy controls using a non-parametric test (Mann-Whitney). Results: Soluble stimulatory molecules GITR (p Citation Format: Bernardo Rapoport, Helen Steel, Teresa Smit, Liezl Heyman, Annette Theron, Nomsa Hlatswayo, Luyanda Kwofie, Lidia Jooste, Farhana Moosa, Carol Ann Benn, Simon Nayler, Ronald Anderson. Dysregulation of soluble immune checkpoint proteins in newly - diagnosed early breast cancer patients [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS17-36.