Glycohistochemistry of endogenous lectins in cutaneous cancer

Plant lectins have been applied to define the profile of certain carbohydrate determinants in routinely processed sections of specimens from cutaneous neoplasia. To facilitate detection of endogenous receptors with specificity to carbohydrates, termed endogenous lectins, biotinylated neoglycoproteins (glycoproteins derived from chemical glycosylation of a histochemically inert carrier protein) were employed on formalin-fixed, paraffin-embedded sections of 40 cases of cutaneous cancer. These included 20 cases of basal cell epithelioma and 10 cases of squamous cell carcinoma as well as 10 cases of malignant melanoma. A mixed pattern of staining extent was seen for the different types of neoglycoproteins. Glycohistochemical controls ascertained that endogenous lectins with specificity for alpha- or beta-galactosides, alpha-mannosides, alpha-fucosides and alpha-glucosides, respectively, bound the neoglycoproteins. Initial biochemical purification from one case of basal cell epithelioma revealed the molecular characteristics of the endogenous beta-galactoside-specific and alpha-mannoside-specific lectins.