CD33 and colorectal carcinoma: Here, CD33+ cells were co-cultured with another CRC cell line, LoVo (Figure 4A), which had a stronger metastasis potential for 48 h and the cell phenotypes were further examined by FCM, showing that the proportion of HLA-DR−CD33+CD11b+ MDSCs was markedly higher when CD33+ cells were co-cultured with LoVo compared with CD33+ cells cultured in medium alone (Figure 4B).