ST6GAL1 and prostate carcinoma: Consistent with ST6GAL1 regulating Siglec-2 and Siglec-3 ligands, we also detected downregulation of sialoglycans that engage Siglec-2 and Siglec-3 in murine RM1 prostate cancer cells depleted of ST6GAL1 (Fig. 5f and g).