Brightplex MDSC, uses a combination of 6 biomarkers to identify different subtypes of Myeloid Derived Suppressor Cells (MDSCs), PMN-MDSCs and M-MDSCs, that had thus far remained difficult to identify by IHC. The presence of these highly immuno-suppressive cells in the tumor microenvironment is associated with a poor prognosis; their depletion is under investigation in several clinical trials.