ST6GAL1 and prostate cancer: Using in vivo models, we find ST6GAL1 promotes the spread of prostate cancer to bone, and reveal the mechanisms involved are multi-faceted, and involve modification of the pre-metastatic nice towards bone resorption to promote the ‘vicious cycle’ of bone metastasis, as well as the regulation of M2 like macrophages and immunosuppressive sialoglycans.