2.5.2. Globosides Globo H and stage-specific embryonic antigen 4 (SSEA 4) have the same precursor, stage-specific embryonic antigen 3 (SSEA3), and therefore sharing a structural motif (Figure 1). Both glycosphingolipids, Globo H and SSEA4, are only different by their terminating monosaccharide, α1-2-linked Fucose and α2-3-linked Neu5Ac, respectively (Figure 1). These glycans are of importance because both have been described in association with cancer. Globo H, a fucosylgalactosylgloboside, was originally characterized by Hakomori and co-workers in a human breast cancer cell line [171]. Inhibitors,research,lifescience,medical Expression of Globo H (both as GSL and glycoprotein) in 143 cases of breast cancer was not correlated with patient survival [172].

Using glycan array a significant difference in anti- Globo H antibody levels in serum of breast cancer patients and healthy donors was demonstrated, and the increase of Globo H in breast cancer stem cells was associated with the disease progression

[53]. Globo H was also found to be expressed in ovarian Inhibitors,research,lifescience,medical cancer [2,173]. 3. Conclusions and Discussion Despite immense progress in research of cancer-associated glycans during the past three decades, this area of glycobiology and molecular oncology still opens broad possibilities for scientific discoveries. A number of regularities of cancer-associated glycosylation were clearly defined. We have screening library mentioned and discussed the main known cancer-associated Inhibitors,research,lifescience,medical glycans involved in breast and ovarian cancer. For example, breast cancer cells express truncated Core 1-based glycans including T, Tn and sTn antigens instead of elongated Inhibitors,research,lifescience,medical O-chains. The expression of sialyl-Lewis antigens is also altered and complex gangliosides are overexpressed in invasive ductal carcinomas. In ovarian cancer, sLex/sLea and their analogues as well as sTn and Ley have been correlated with metastatic potential and patient survival. However, lectins and most monoclonal antibodies, used in classical Inhibitors,research,lifescience,medical studies, are not strictly specific for certain carbohydrate structures but expose some degree of cross-reactivity (for review see [121]). Thus, novel glycan cancer associated epitopes, especially combined glyco-peptide

and -lipid epitopes, presumably specific for certain cancer types/stages/grades are AV-951 still in the now process of identification. We need to know more about TACA, the structure of TACA-bearing glycoconjugates, the role of their molecular architecture in vivo for immune recognition, alterations of glycosyltransferase expression in cancer, and, finally, the molecular mechanisms of their action. Currently, the mechanisms defining malignancy are fairly understood only for sLex and sLea, as these TACA mediate binding of tumor cells to microvascular endothelium through E-selectin expressed on the endothelial cells. The biochemical mechanisms of action of other cancer-associated glycans in cancer progression are still under evaluation [5,9,11].