An especially intriguing “cancer vaccine” approach to MUC1 employs metabolic glycoengineering strategies (a technology described in more detail in section Metabolic Glycoengineering) that incorporate non-natural sialic acids into glycan structures that increase their immunogenicity [as shown in Figure 5B and described in a series of papers primarily from the Guo group (132–135)]. This evidence concerns the gene MUC1 and cancer.