Recent data interrogating the TCGA show upregulation of TGF-β1 in a number of cancers including CRC and this correlates with the markers expressed on M-MDSCs, CD14 and CD33, but not with the G-MDSC marker CD66b [35] (PMN-MDSCs are CD33dim rather than the high expression seen on M-MDSCs [36]). Here, CD33 is linked to cancer.