MORPHOLOGICAL AND IMMUNOHISTOCHEMICAL CHARACTERISTICS OF ENDOMETRIAL LAYERS IN WOMEN OF REPRODUCTIVE AGE WITH ENDOMETRIAL HYPERPLASIA WITHOUT ATYPIA
Authors: KHASKHACHYKH D.A. 
Published: February 2024

Immunohistochemical staining may be useful for the differential diagnosis of endometrial hyperplasia (EH) without/with atypia and carcinoma. Several immunohistochemical biomarkers have already been investigated for use as diagnostic adjuncts in the diagnosis and classification of EH and may also predict progression from EH to carcinoma. However, the optimal molecular biomarker would be one that could reliably distinguish between hyperplastic benign with/without risk of recurrence, precancerous (hyperplastic atypical) and malignant endometrium, and indicate/predict transition between these three groups. To date, no candidate has been found to fully fill this role, so the search is ongoing.
Aim. To study the morphological and immunohistochemically features of the structure of all layers of the endometrium, divided into functional and non-functional zones, which may have an impact on the development of endometrial hyperplasia
Materials and methods. The study was performed on endometrial morphological material obtained by diagnostic biopsy from 21 women with abnormal uterine bleeding (AUB) in the gynecological department of the Dnipro Clinical Hospital No. 9 in Dnipro during 2022-2023. The study investigated the expression of the biomarkers ER, PgR, Ki67, CK7, and CK8 in women with endometrial hyperplasia without atypia and secretory endometrium.
Results. In women with EH without atypia, the expression of ER in the stroma spontaneously increases, while epithelial cells do not show sensitivity to estrogen. The expression of PgR in the glands spontaneously increases, while the expression of PgR in the stroma is low. This may indicate that stromal cells may be less sensitive to progesterone. High expression of Ki67 in endometrial hyperplasia causes active processes of cell proliferation, while low expression of Ki67 in normal endometrium indicates its physiological state. These data can be useful for diagnosis and detection of pathological changes of the endometrium. SK7 is expressed in epithelial cells, even with increased numbers. Normally, during functional observations of the endometrium, the expression of SK7 in epithelial cells is also observed. The functional zone is a layer of the endometrium that undergoes cyclical changes depending on the menstrual cycle of a woman. In this case, there is a regular renewal of cells expressing CK7, which remains one of the typical markers of epithelial cells. The analysis of SK7 expression allows us to detect differences in the processes of cell proliferation and differentiation between endometrial hyperplasia without atypia and normal endometrium. These data coincide with the findings of other authors, are important for a deeper identification of pathophysiological mechanisms associated with endometrial hyperplasia, and also include additional markers for the diagnosis and prognosis of this condition.
Conclusion The study results suggest that the expression of ER, PgR, Ki67, CK7, and CK8 may be associated with the development of EH without atypia. Further studies are needed to confirm these findings and to investigate the role of other biomarkers in the pathogenesis and diagnosis of EH.