Immunogenic compositions, cancer vaccines and methods for treating cancer are provided. Compositions comprising: (a) a glycan such as Globo H or an immunogenic fragment thereof, wherein the glycan is conjugated with a carrier protein by a linker such as para-nitrophenyl; and (b) an adjuvant comprising glycolipid capable of binding CD1d on a dendritic cell, such as an α-galactosyl-ceramide derivative, wherein the immunogenic composition induces an immune response that induces a higher relative level of IgG isotype antibodies as compared to IgM isotype antibodies, are provided. Immunogenic compositions comprising the carrier protein diphtheria toxin cross-reacting material 197 (DT-CRM197) and the adjuvant C34 are provided. Antibodies generated by immunogenic compositions disclosed herein further neutralize at least one of the antigens Globo H, stage-specific embryonic antigen-3 (SSEA-3) and stage-specific embryonic antigen-4 (SSEA-4). Therapeutics against breast cancer stem cells comprising immunogenic compositions comprising Globo H, SSEA-3 or SSEA-4 conjugated with DT-CRM197.