CD274 and cancer: While the percentage of Tregs and MDSCs was similar between cancer patients and healthy donors, cancer patients had higher levels of a Treg subset that expressed CTLA-4 (p=0.0280, Figure 5D), which is a suppressive marker for these regulatory cells [17], as well as increased levels of PD-L1+ MDSCs (p=0.0088, Figure 5E), a marker that has been implicated in suppressive function [18].