Fig. 1.

Patients with glioblastoma (GBM) have elevated levels of myeloid-derived suppressor cells (MDSCs) compared with age-matched healthy donors and other cancer patients. Peripheral blood mononuclear cells (PBMCs) from patients with newly diagnosed GBM, healthy age-matched donors, and other patients with cancer were isolated and stored in liquid nitrogen. Cells were thawed, washed, and blocked with human immunoglobulin G and then immediately stained at 4°C with monoclonal antibodies to CD14, CD15, CD33, and HLA-DR. Cells were fixed with 1% paraformaldehyde, then acquired and analyzed by multicolor flow cytometry.