Tumor associated carbohydrate antigens (TACAs) are a class of glycans with important structural and signaling functions playing a major role in cell proliferation, differentiation, and apoptosis relevant to oncology. Tumor cells expressing TACAs influence prognosis and survival of cancer patients. Careful consideration must be given to structural aspects during rational design of small molecule therapeutics that mimic the molecular topology of different classes of TACAs even though they are chemically dissimilar but functionally equivalent molecular structures.