Bauhinia purpurea (BPA) binding to normal and neoplastic thyroid glands

Biotinylated bauhinia purpurea agglutinin (BPA) was studied, using the ABC method, in different thyroid gland conditions (26 follicular adenomas, 39 papillary carcinomas, 15 follicular carcinomas, and 10 normal thyroids), to determine whether specific lectin binding patterns were developed during malignant transformation that could enable the distinction of carcinoma from adenoma. In normal thyroids, BPA was very rarely and faintly reactive with follicular cells. In neoplastic conditions, BPA binding profiles for follicular adenoma were essentially identical to those of normal follicles, whereas BPA unequivocally reacted with follicular carcinoma and papillary carcinoma. BPA reacted more strongly with cells of papillary structures than with those forming solid nests and follicles. In papillary carcinoma, BPA binding was observed mostly in the apical surface and cytoplasm of carcinoma cells, whereas a diffuse cytoplasmic binding pattern was predominant in follicular carcinoma. Neuraminidase treatment had little or no effect on either normal or adenomatous follicular epithelium, whereas in follicular carcinoma, the number of positive cells and the staining intensity was increased. These findings suggest that BPA would be useful for the differential diagnosis of papillary and follicular carcinomas, and less consistently so, for differentiating follicular carcinoma from follicular adenoma. Peanut agglutinin with similar sugar specificity was not reactive with follicular cells either in normal or neoplastic glands.