Immunohistochemical staining of GLUT1 in benign, hyperplastic, and malignant endometrial epithelia

BACKGROUND. Aberrant expression of the facilitative glucose transporter, GL UT1, is found in a wide spectrum of epithelial malignancies. The current st udy describes an immunohistochemical study of GLUT1 expression in benign, h yperplastic, and malignant endometrial epithelia. METHODS, One hundred sixteen formalin fixed, paraffin embedded sections of benign, hyperplastic, and malignant endometrial epithelium were immunostain ed with rabbit anti-GLUT1 antibody using the streptavidin-biotin method. RESULTS. Proliferative, secretory, and atrophic endometrium were not staine d with GLUT1 antiserum. Rare, minute foci of tubal metaplasia stained posit ively. Simple and complex endometrial hyperplasias were consistently GLUT1 negative. All specimens of atypical hyperplasia had foci that were positive for GLUT1. All endometrial adenocarcinomas were GLUT1 positive. CONCLUSIONS. The results of the current study appear to indicate that 1) ab errant overexpression of GLUT1 is a consistent feature of endometrioid aden ocarcinoma; 2) GLUT1 immunostaining may be useful in distinguishing benign hyperplasias from hyperplasias that are associated strongly with malignancy ; and 3) some or all cases of atypical hyperplasia may be neoplastic rather than hyperplastic, given the existence of a molecular defect common to thi s hyperplastic subtype and endometrioid adenocarcinoma. (C) 2000 American C ancer Society.