Siglecs in immunotherapy: current clinical landscape and prospects

Siglecs are a family of sialic acid-binding immunoglobulin-like lectins that regulate immune signaling and maintain homeostasis through glycan recognition. Despite their central role in immune modulation, their therapeutic potential remains underexplored. Advances in antibody engineering, glycan biology, and molecular design have greatly expanded our understanding of Siglec-ligand interactions, revealing their promise in regulating immunosuppression in cancer and autoimmunity. The current clinical landscape shows trials targeting mainly Siglec-2 and -3, with a predominant focus on hematological cancers. This review evaluates preclinical and recent clinical progress in Siglec-targeted immunotherapies, emphasizing mechanisms, safety, and efficacy, and proposes a translational framework to accelerate therapy development and broader immunotherapy advancements.