A study by Fallah et al. involving 109 patients with non-metastatic urothelial carcinoma (UC), regardless of prior treatment, revealed that UnC-MDSCs (CD33+HLA-DR−CD14−CD15−) were the dominant subtype in whole blood (46%), while PMN-MDSCs (CD33+HLA-DR−CD14−CD15+) prevailed in peripheral blood mononuclear cells (PBMC) at 41%. Here, CD33 is linked to urothelial carcinoma.