Frutalina, lectina α-D galactose ligante de Artocarpus incisa L.: um estudo com câncer de mama

Abstract

Lectins are proteins which bind specifically to carbohydrates. Recently considerable interest has been devoted to cell surface carbohydrates, since they are related to differentiation and maturation phenomena. Neoplastic transformation in cells is associated to altered cell surface membranes, particularly with an abnormal composition. This may determine of neoplastics cell characteristics. Lectins have been used as tools in many areas of diagnostic investigation especially related to changes in the expressions of membrane and cytoplasmatic carbohydrates. In this study it has been examined the expression of glycoconjugates especific to Artocarpus incisa lectin (frutalina) in various histological stages of tumor progression in the breast tissues. These included normal epithelium, apocrine metaplasia, ductal hyperplasia, without and with atypia, ductal carcino-ma in situ, invasive ductal carcinoma and nodal metastasis. This tissue was stained to bind to the lectin using two different histochemical techniques: frutalina reacting directly (Technique I) and antibody anti-frulalina as a bridge; antibody anti-frutalina reacting directly (Technique II). In both techniques the staining was more frequent in malignant than in benign breast epithelium. Most of the ductal carcinomas in situ stained the membrane as well as the citoplasm. All invasive ductal carcinomas were stained by frutalina. During the tumor progression there occurred modifications on the glycoconjugate cellular surfaces showing galactose residues. The most interesting aspect of this study was that the antibody anti-frutalina did not stained any of the cases of atypical hyperplasia