Immunohistochemical Expression of “HE4” in Endometrial Hyperplasia versus Endometrial Endometrioid Carcinoma

Abstract

Aim 
 Endometrial cancer is the most common cancer of the female genital tract. No effective biomarkers currently exist to allow for an efficient risk classification of endometrial carcinoma. Human epididymis protein 4 (HE4) overexpression is first observed in ovarian cancer tissue and subsequent research has shown that the HE4 overexpression has also been observed in patients with endometrial carcinoma. To our knowledge, this marker was evaluated in small number of research studies in cases of endometrial carcinoma versus hyperplasia. This has inspired us to test for immunohistochemical expression of HE4 in endometrial endometrioid carcinoma and hyperplastic endometria and to correlate HE4 expression with various prognostic pathological parameters including International Federation of Gynecology and Obstetrics (FIGO) grading and staging.
 Methods 
 Immunohistochemical staining for HE4 was performed on paraffin-embedded sections of forty cases of endometrial endometrioid carcinoma and thirty cases of endometrial hyperplasia: including 15 cases of non-atypical hyperplasia and 15 cases of atypical hyperplasia. A histochemical score was used to evaluate HE4 expression by the tumor cells.
 Results
 In this study, HE4 overexpression level was significantly higher in endometrial endometrioid carcinoma than endometrial hyperplasia and significantly higher than non-atypical endometrial hyperplasia (P<0.05). HE4 strong expression was detected in 20% of atypical endometrial hyperplasia, but no statistical significance was detected between atypical hyperplasia and endometrial carcinoma. HE4 overexpression showed statistically significant positive correlation with FIGO grading, FIGO staging, and depth of myometrial invasion.
 Conclusion:
 During interpretation of endometrial biopsies of atypical hyperplasia, HE4 strong expression might raise the possibility of the presence of coexisting adenocarcinoma not biopsied or even warning of a near future malignant transformation. Also, strong expression of HE4 by tissue biopsy of adenocarcinoma should be reported as this might predict higher grade and stage of the tumor, a point that should be considered by surgeons while performing hysterectomy. These results should be further confirmed by extending the study on a large scale, correlation of HE4 expression with the molecular classification of Tumor Cancer Genome Atlas and long term follow up are required to establish the prognostic significance of HE4 expression in endometrial carcinoma and atypical hyperplasia.
 Keywords: Endometrial carcinoma, Endometrial hyperplasia, HE4, Immunohistochemistry.