EXPRESSION OF THE OLINKED NACETYLGLUCOSAMINE CONTAINING EPITOPE H IN NORMAL MYOMETRIUM AND UTERINE SMOOTH MUSCLE CELL TUMORS

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Aim. In the present study, we focused on uterine smooth muscle cell tumors and their adjacent normal myometrium to gain further insight into the expression patterns of epitope H in human tissues. Material and Methods. The indirect immunoperoxidase method was applied using the mAbH and the monoclonal anti-cytokeratin 8 antibody (AbCK8) in 50 cases of typical uterine leiomyomas and in five of uterine leiomyosarcomas. Results and Discussion. Epitope H showed: 1) intense immunohistochemical expression in 46% and moderate expression in 54% of uterine leiomyomas; 2) intense immunohistochemical expression in 40% and moderate expression in 60% of uterine leiomyosarcomas; 3) no difference in the immunohistochemical expression between leiomyomas and their adjacent myometrium and between leiomyosarcomas and their adjacent myometrium; 4) immunohistochemical expression of cytokeratin 8 was not detected in the normal and neoplastic smooth muscle cells; 5) Western immunoblotting showed that in the smooth muscle cells of the myometrium and leiomyomas, epitope H is localized in four polypeptides with molecular weights of 100, 61, 59, and 54 kDa, and 6) Western immunoblotting did not detect cytokeratin 8 in the normal and neoplastic smooth muscle cells. Conclusions. The present results indicate fluctuations of the epitope expression levels in uterine smooth muscle cell tumors and their adjacent myometrium. Furthermore, indicated that cytokeratin 8, without being present in the cells of the myometrium, leiomyomas and leiomyosarcomas, shares its epitope H, which contains its unique sugar O-Nacetylglucosamine residue, with four other unrelated polypeptides produced by the normal and neoplastic smooth muscle cells. This should be considered when using anti-cytokeratin 8 antibodies in immunohistochemistry against smooth muscle cell tumors to avoid false positive immunohistochemical results.