Galectin-3, an endogenous lectin, as a tool for monitoring cell differentiation in head and neck carcinomas with implications for lectin-glycan functionality

Objective-Galectin-3 is an endogenous lectin that reacts with glycan epitopes of membrane and extracellular glycoproteins, including integrins, fibronectin, laminin and tetraspanins. Its expression, and also the presentation of its glycoligands, is controlled in a differentiation-dependent manner in squamous epithelia. The aim of this study was to monitor the carbohydrate-dependent binding of labeled galectin-3 to primary head and neck squamous cell carcinomas (from the tonsil, base of the tongue and larynx) and lymph node metastases. Material and Methods-Double labeling (using antibodies against desmoplakin-1, Ki-67 and cytokeratins) at the single-cell level was employed to cytologically characterize cells reacting with galectin-3. Results-Galectin-3 binds a non-proliferating pool of tumor cells. Colocalization of galectin-3 binding sites with desmosomal proteins may indicate a role for this endogenous lectin in the formation of intercellular contacts of the desmosomal type. Cytokeratin-10-positive tumor cells also presented galectin-3-reactive binding sites on the surface; however, cytokeratin-10-free cells were also recognized by this lectin. Conclusion-These findings intimate that galectin-3 may represent a new tool for monitoring the degree of cell differentiation in carcinomas originating from the transformation of squamous cell epithelia.