Immunohistochemical features of cyclooxygenase-2 expression in endometrial hyperplasia without atypia

Abstract

Hyperplastic processes of the endometrium without atypia have been an urgent problem for researchers around the world for a long time, given the current position of cancer alertness and violations of reproductive function. Objective. To study immunohistochemically the expression level of the new biomarker - cyclooxygenase-2 (COX-2) in various types of endometrial hyperplasia without atypia in samples of altered endometrial tissue from 30 patients of reproductive age (39.47 ± 1.1 years). Materials and methods. Endometrial hyperplasia manifested as glandular in 17 patients (56.7%), glandular-cystic - in 11 (36.7 %), stromal and cystic-atrophic forms – in one case for each form (3.3 %). The study was carried out according to the standardized protocol of primary monoclonal antibodies COX-2 manufacturer (Thermo Scientific, rabbit, working dilution 1:50-1:100) using the visualization system “UltraVision Quanto Detection System” of the Thermo Scientific company in paraffin sections. Samples were stained with methylene green and mounted using Canadian balsam. In this work we used the methods of optical light microscopy (Olympus BX 51,Japan) and immunohistochemistry. Localization of staining (gland/stroma) and intensity score were determined by the stain intensity (0 – no staining, 1 – weak, 2 – moderate, 3 – strong). Results. The presence of COX-2 expression in the stromal component of the endometrial tissue samples was found from the majority of the examined patients (in 24 cases, 80.0%), however, its levels were recorded only as weakly positive. In glandular endometrial structures, in the presence of endometrial hyperplasia without atypia, the levels of COX-2 expression were characterized by some variability and dependence on structural localization. Thus, in 16 patients (66.7 %) its weakly positive expression was revealed, in 7 examined persons (29.2 %) – moderately stained material. Intensive COX-2 expression was determined in one case (4.1%). COX-2 expression in the hyperplastic endometrium was not detected in 6 samples (20.0%). Morphological signs of chronic endometritis were revealed in 9 investigated samples (30.0 %) – lymphoplasmacytic infiltration, altered pseudostratification of glandular epithelium, lysis of individual epithelial gland structures which were confirmed immunohistochemically: positive expression of CD138 in plasma cells. Conclusions. The study data can serve as one of the criteria for the differential approach to a choice of treatment tactics in patients with a hyperproliferative endometrial pathology including prevention of possible malignant transformation.

Keywords

• endometrial hyperplasia
• cyclooxygenase-2
• immunohistochemistry