STS and cancer: When cancer advances to the malignant stage, giantin is inactivated [21], which leads to loss of C2GnTs [22, 59] and shifts Golgi targeting of all other glycosylation enzymes to GM140‐GRASP65 site, culminating in the formation of tumor‐associated carbohydrate antigens (TACAs), which include Tn, sTn, T, sTs, and sLea as shown in Fig. 8B [29, 30, 31, 32, 33, 34].