Aberrant sialylation in cancer: From molecular mechanisms to potential therapeutics

Sialylation, a dynamic post-translational modification catalyzed by sialyltransferases and counterbalanced by neuraminidases, entails the attachment of sialic acids to the terminal residues of glycoproteins and glycolipids. This modification profoundly influences diverse biological processes, including early embryogenesis, neurodevelopment, maintenance of stem cell pluripotency, and oncogenic transformation. In cancer, aberrant sialylation manifests as altered linkage patterns and dysregulated expression of sialylated glycans, which directly drive malignant behaviors such as uncontrolled proliferation, enhanced adhesion and invasion, immune evasion, and therapy resistance. Deciphering the underlying molecular mechanisms is therefore crucial for advancing our understanding of tumor biology. In this review, we systematically summarize recent advances in the study of sialylation in cancer, with a focus on the biological functions of distinct sialyltransferases and neuraminidases. We further discuss the diagnostic, prognostic, and therapeutic implications of targeting sialylation, highlighting its emerging potential as a promising avenue for cancer treatment.