CD33 and neoplasm: The aberrantly sialylated tumour-specific glycotopes reduce cancer immunogenicity by the hiding of cell surface antigens, however, the tumour immune evasion is mainly facilitated by immune receptor families, such as the most of CD33-related sialic acid-binding immunoglobulin like lectins (Siglecs), that recognize cancer sialoglycans and transmit suppressive signals [14,15].