CDW75 ANTIGEN EXPRESSION IN BREAST-LESIONS

Alterations on the cell surface of the oligosaccharide portion of glyc oproteins and glycolipids are thought to play a role in tumorigenesis. Sialyltransferase catalyzes the incorporation of sialic acid to the c arbohydrate group of glycoconjugates. Sialyltransferase has been found elevated in different tumour tissues and in the serum of cancer patie nts. In the present study we have examined the expression of the beta- galactosyl alpha2,6-sialyltransferase requiring epitope CDw75, with th e monoclonal antibody HH2. 142 breast lesions were included. 21 % of t he carcinomas in situ and 35 % of the invasive carcinomas showed a dif fuse cytoplasmic staining. Seven cases of invasive carcinomas also sho wed a distinct membrane immunoreactivity. We found no correlation betw een reactivity for CDw7S in malignant lesions and their metastatic pot ential. Only five out of 11 primary tumours with metastases expressed CDw75 in the primary tumour. In the benign lesions, there was a positi ve reaction in proliferating lesions, e.g. intraductal papillomas (2 o ut of 3 cases) and in epithelial proliferations in fibrocystic disease (10 out of 14 cases). None of the four fibroadenomas and phyllodes tu mours and only one out of 22 cases of normal breast tissues showed imm unoreactivity for HH2. In the malignant lesions, CDw75 was more freque ntly expressed in the carcinomas of high malignancy grade. The high fr equency of immunoreactivity among the benign breast lesions can be ind icative of activation of the epithelial cells.