Article
Expression of inhibin/activin subunits (alpha, betaA and betaB) in normal and carcinogenic endometrial tissue: possible immunohistochemical differentiation markers
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Published: | March 20, 2006 |
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Introduction: Inhibins (INH) are dimeric glycoproteins, composed of an alpha-subunit (INH-a) and one of two possible beta-subunits (INH-bA or -bB), with substantial roles in human reproduction and in endocrine-responsive tumours. Aims of this study were to determine the frequency and tissue distribution of INH-a, -bA and -bB in normal and malignant endometrium.
Materials: Samples were obtained from normal (n=46), atrophic (n=8) and endometrioid carcinoma tissue (EC; G1=93; G2=32; G3=14). The immunohistochemical reaction in intermediate trophoblast was analyzed with a semi-quantitative score (IRS) and statistical analysis was performed.
Results: INH-a, -bA and -bB were immunolabelled in normal and malignant endometrium.INH-a was significantly higher in normal compared to malignant endometrial tissue, showing a cyclical variation throughout the menstrual cycle. EC G3 did not express this subunit. INH-bA and bB showed specific staining reactions within the tumour cells. INH-bA highest intensity was observed in normal secretory phase compared to adenocarcinomas (p<0.05). For INH-bB, the significantly highest expression was noted EC G3 compared to EC G2 (p<0.05) and atrophic endometrial tissue.
Conclusion: INH-a was expressed in a declining relationship, suggesting a tumour suppressive function in EC. Interestingly, a high expression of INH-bB was observed in EC G3 compared to G2, suggesting an important role in endometrial carcinogenesis. However, the utilisation as specific tumour markers of these subunits remains still unclear.