To more detailed learn the dynamic change and clinical relevance of circulating and tumor-infiltrating Lin−/lowHLA-DR−CD11b+CD33+ MDSC in the colorectal cancer, in this study, we harvested the blood from 64 patients with varying stage of colorectal cancer and tumor and matched paraneoplastic tissues from 5 patients with stage III colorectal cancer, subjected them to multicolor flow cytmetric analysis of percentage, absolute number and phenotype of MDSC, and finally characterized their immunosuppressive functions. This evidence concerns the gene CD33 and neoplasm.