The aberrant overexpression of mucins in cancer cells and their altered glycosylation may lead to different, quite opposite effects on tumor immunity, from the expression of cancer-specific immunodominant glycoepitopes (TF, Tn [GalNAca1α-], sTn [NeuNAc-α2-6GalNAc α1-]) to the reduction of T cell effector functions [50]. The gene discussed is TF; the disease is cancer.