EEF1A2 and cancer: STn antigen is the most widely studied glycotype in cancer, and its biosynthesis is controlled by the ST6 N-acetylgalactosaminide α-2,6-sialyltransferase 1 (ST6GALNAC-I), which catalyzes the transfer of NeuNAc to the O-6 position of GalNAc residues linked to Ser/Thr.