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The purposes of this research were 1- to study the expression of MUCI peptidic and carbohydrate epitopes in normal, benign and malignant breast epithelia and 2- to correlate this expression with breast cancer disease stage. An immunohistochemical approach was performed in 81 tissues obtained from normal, benign and malignant sections; studies were performed following standard procedures. Three anti-MUC1 peptide core monoclonal antibodies (MAbs), C595, HMFGI and SM3 were used and 4 anti carbohydrate antigens MAbs: sLewis x (KM93), Lewis x (KM380), Lewis y (C 14) and Tn. Statistical analysis was done employing a Principal Component Analysis with Kendall correlations. Malignant tissues expressed peptidic and carbohydrate MUC1 epitopes with high intensity and elevated percentages of positivity; MUC1 protein core was reactive in 89% in stage I, 87% in stage II, 75% in stage III and 83% in stage IV. SM3 MAb showed its highest staining (83%) in tumors belonging to stage IV patients. Lewis x and sLewis x were found coexpressed with a correlation value of 0.5487; Lewis y diminished its expression from 67% in stage I tumors to 50% in stage IV while Tn showed the lowest expression respect to the other antigens in any of the stages. Reactivity of benign and normal samples was restricted to the apical cell surface. Statistical analysis showed a separation between normal and dysplasia versus cancer samples (p<0.05). Conclusion: carbohydrate antigens are expressed in breast tissue under different patterns, intensity and extension being predominant in cancer cells. [ABSTRACT FROM AUTHOR]

MUC I is a highly glycosylated mucin with a large extracellular domain, a transmembrane fraction as well as a 72-aminoacid cytoplasmic tail (CT). The present research was developed to study the pattern of MUC 1 mucin expression in breast carcinoma with an anti MUCI cytoplasmic tail (CT) MAb since it is a reliable indicator of the abundance of cell-associated MUC1. A total of 98 pretreatment tumor samples were obtained from breast cancer patients; all cases were typed as invasive adenocarcinoma; disease staging, histopathological type and grade of differentiation were established. Samples from normal and benign conditions were also included. Immunohistochemistry (IHC) was performed following standard procedures. The pattern of reaction was classified as lineal when the plasmatic membrane was reactive, cytoplasmic and mixed. Subcellular fractions were prepared followed by SDS-PAGE and Western blots analysis. The antibody employed was CT2 monoclonal antibody (MAb) directed against the last 17 aminoacids of the MUCI-CT. IHC showed a high percentage of positive staining in about 90% specimens; frequently, 50% or more tumor cells stained either with a homogeneous distribution, or restricted to some areas of the sample. Benign and normal samples showed a more restrictive pattern usually confined to the plasmatic membrane. By Western blot, subcellular fractions derived from malignant samples showed different bands of reaction at approximately 30 kDa (the most intense), at 60-50 and at 180 kDa. Conclusions: the pattern of expression of MUC I CT in breast epithelium may constitute a better indicator for MUC 1 production since it does not depend on glycosylation. [ABSTRACT FROM AUTHOR]

The present study was undertaken to study the relationship of tumor-associated antigens with colorectal carcinoma by means of immunohistochemistry (IHC) with a panel of monoclonal antibodies (MAbs). Materials and Methods: Tumor tissue samples were studied from 59 patients with colorectal cancer (Dukes stages B, C and D), 24 benign colorectal conditions and 24 colorectal normal mucosa. Immunohistochemistry was performed following standard procedures; MAbs against the following tumor associated antigens were included: MUC2 mucin (PMHl), MUCl (C595) carcinoembryonic antigen (CEA, C365), colonic glycolipid (C505), normal colorectal antigen (NCA, C198), Lewis x (KM380), sialyl Lewis x (KM93), Lewis y (C 14 MAb) and Tn hapten. Immune reaction was graded according to positive staining, intensity and distribution. Results: in colorectal cancer tissue sections, a high expression of tumor antigens associated with metastatic dissemination was found: Lewis x, 62%; MUC 1 and MUC2, 47%; Lewis y, 46% and slaty] Lewis x, 44%; Tn was positive in 36%, CEA in 32%, NCA, 44% and colonic glycolipid in 82%. Benign samples showed a remarkable positive expression of glycolipid antigen, WC 1, MUC2, NCA and Lewis x; an interesting feature was the expression of MUC 1 in invasive areas of several specimens. Normal tissue samples mainly reacted with glycolipid antigen, NCA and Lewis x. Conclusion: Colorectal cancer expresses strongly a variety of tumor antigens, which are involved in recurrence and metastatic processes. [ABSTRACT FROM AUTHOR]