,12,13 Upregulation of ST6GAL1 impacts oncogenic behaviours and plays a critical role in tumour transformation, survival, growth, metastasis, immune evasion and chemoresistance.14, 15, 16, 17 In prostate cancer, a rewiring of the tumour glycome has been linked to disease progression18,19 and both ST6GAL1 and larger branched sialylated N-glycans are increased in prostate tumour tissue relative to normal prostate tissue.18 Here, ST6GAL1 is linked to prostate cancer.