Aberrant glycosylation of the extracellular domain of tumor-associated MUC1 leads to the exposure of immunogenic core peptide epitopes, and to the presence of tumor-associated carbohydrate antigens (TACA), such as the blood-group-related antigens Tn, sialylTn, and the Thomsen-Friedenreich (TF or T) antigen [26,27]. The gene discussed is TF; the disease is neoplasm.