Described herein are synthetic glycan conjugates, immunogenic compositions thereof, vaccines thereof, and kits thereof. The present invention further provides methods of using the synthetic glycan conjugates, immunogenic compositions, or vaccines thereof to treat and/or prevent and/or diagnose proliferative diseases such as cancer. The provided glycan conjugate comprises a carrier and a glycan moiety of Formula (I-i) or Formula (I-ii): (structurally represented).