ST6GAL1 and cancer: Additionally, the soluble form of ST6Gal I possesses sialyltransferase enzymatic activity, but unlike the Golgi-associated form, did not sialylate integrin β1 to a significant degree, suggesting that soluble ST6Gal I, possibly in cooperation with the Golgi-bound form, may participate in cancer progression and metastasis before being secreted from cancer cells, independent of intergrin β1-sialylation.