EXPRESSION OF EPITOPES OF THE TUMOR-ASSOCIATED GLYCOPROTEIN-72 AND CLINICOPATHOLOGICAL CORRELATIONS IN MAMMARY CARCINOMAS

We analysed the immunohistochemical expression pattern of the distinct carbohydrate epitopes of the TAG-72 molecule, defined by the monoclon al antibodies (MAbs) B72.3, CC-49 and CC-83, in 92 breast carcinomas o f different histological type, and in other histological components id entified in the mammary tissue samples studied. The results were corre lated with the chinico-pathological characteristics of the tumours, an d with their proliferative activity, assessed by thymidine labelling i ndex (TLI). Expression of the TAG-72 epitopes was detected in all the tumour histotypes analysed, but patterns of immunoreactivity tended to vary in relation to type and level of differentiation. The comparativ e analysis of the reactivities of the three anti-TAG-72 MAbs revealed differences in their ability to recognise neoplastic lesions. MAb CC-4 9 reacted with the highest percentage of tumours (82%), and also tende d to yield the highest percentages of immunoreactive cancer cells, whi le B72.3 and CC-83 reacted with lower percentages of tumours (respecti vely, 55 and 51%), and identified lower percentages of immunoreactive cells. High levels of expression of the three TAG-72 epitopes were det ected in areas of in situ ductal carcinoma. Comparatively lower levels of immunohistochemical positivity were found in atypical epithelial h yperplasia, normal mammary epithelium and epithelium with cystic disea se. TAG-72 epitope expression was correlated with prognostic parameter s. The synchronous expression of the three epitopes significantly corr elated with large tumour size (> 2 cm), and with high histological gra de. No correlations could be demonstrated between TAG-72 phenotypes an d nuclear grade, lymph node status and proliferative activity (high ve rsus low).