Inhibin/activin betaE-subunit in uterine endometrioid adenocarcinoma and endometrial cancer cell lines: From immunohistochemistry to clinical testing?

Abstract

Objective Inhibins and activins are important regulators of the female reproductive system and have also been described to be involved in gynecologic cancer development. A new inhibin/activin subunit betaE has been identified, but only limited data on its expression in human uterine adenocarcinomas and endometrial cancer cell lines exist. Methods A series of 223 uterine endometrial adenocarcinomas were immunohistochemically analyzed with a specific antibody against the inhibin betaE-subunit. In addition, established endometrial cancer cell lines were analyzed for the synthesis of the inhibin betaE subunit by immunofluorescence and RT-PCR analysis. Results In this analysis, the inhibin betaE staining intensity was associated with histological grading along with a significant decrease in cases with ovarian invasion. However, inhibin-betaE did not affect patient survival nor did it constitute an independent prognostic parameter in endometrial adenocarcinoma patients. Additionally, the inhibin/activin betaE-subunit was found to be expressed in the human endometrial carcinoma cell lines HEC1a, HEC1b, Ishikawa, and RL95-2, although the level of expression was found to be highly differing among the cancer cell lines tested. Conclusion The isolated analysis of the inhibin betaE subunit might be of minor prognostic value in identifying high-risk patients. However, its differential expression in cancer of different histological differentiation and ovarian metastasis suggests a putative but yet undefined role in endometrial carcinogenesis. Whether this novel and not well studied inhibin subunit has a substantial function in the pathogenesis and malignant transformation of human endometrium is still under investigation.