ST6GAL1 and cancer: Moreover, in ST6GAL1 K.O. cells, an increase in the trastuzumab-induced stabilization of ErbB2-, EGFR- and ErbB3-containing dimers at the cell membrane was observed in parallel with the downregulation of ErbB2 and EGFR intracytoplasmic phosphorylation, which has been previously reported in other epithelial-derived human cancer and nonmalignant in vitro models [14, 32].