Immunohistochemical Analysis of GATA2 Expression in Endometrium and its Relationship with Hormone Receptor Expression in Benign and Premalignant Endometrial Disorders

Abstract

The GATA gene family encodes highly conserved zinc-finger transcription factors that facilitate the development and function of multiple organ systems including the uterus. In the endometrium, GATA2 functions in a positive autoregulatory loop with the progesterone receptor (PGR) and colocalizes with PGR on chromatin to promote PGR transcriptional programs. GATA2 also has PGR-independent functions that maintain endometrial cell identity, and GATA2 transcripts reportedly are down-regulated in endometrial disorders including endometriosis. This event is accompanied by a reciprocal increase in GATA6. Here, we applied custom anti-GATA2 monoclonal antibodies and performed GATA2 immunohistochemistry (IHC) on patient endometrial tissues corresponding to proliferative, secretory, inactive, and hormone-treated endometrium, as well as endometriosis and endometrial atypical hyperplasia/endometrioid intraepithelial neoplasia (EAH/EIN). We also performed IHC for the estrogen receptor, PGR, and GATA6 in relevant groups. The results reveal a tight correlation between GATA2 and PGR expression in the glandular and stromal cells of benign endometrium. GATA2 expression is markedly reduced in stromal but not glandular cells in endometriosis and EAH/EIN. This reduction in GATA2 expression does not lead to a detectable increase in GATA6 expression in endometriosis. Although average glandular GATA2 expression was preserved in endometriosis and EAH/EIN cases, its expression was decoupled from PGR, implying that alternative pathways regulate GATA2 levels in these disorders. Our findings indicate that GATA2 dysregulation is a feature of endometriosis and EAH/EIN, and support a model whereby loss of stromal GATA2 in these disorders contributes to their progesterone insensitivity.

Keywords: Endometriosis; Endometrium; GATA2; Hyperplasia; Progesterone receptor.

Fig. 1

GATA2, ER, and PGR immunohistochemistry in normal cycling endometrium. A Representative sections of proliferative and secretory phase endometrium stained for H&E and IHC for GATA2, ER, and PGR. B-C Percent GATA2, ER, and PGR positive nuclei in (B) glandular and (C) stromal cells from proliferative and secretory phase endometrium. Statistical comparisons made within individual markers. D-E Correlation between percent cells positive for GATA2 and either ER or PGR in (D) glandular and (E) stromal endometrial cells. All IHCs are DAB with hematoxylin counterstain. NS = not significant, *p < 0.05, **p < 0.005, ***p < 0.0005, ****p < 0.00005. Scale bar = 50 microns

Fig. 2

GATA2 immunohistochemistry in hormone treated endometrium, inactive endometrium, endometrial polyps, and endometrial atypical hyperplasia/endometrioid intraepithelial neoplasia. A Representative H&E and GATA2 IHC images. B-C Percent GATA2 positive nuclei in (B) glandular and (C) stromal cells. All IHCs are DAB with hematoxylin counterstain. NS = not significant, ****p < 0.00005. Scale bar = 50 microns

Fig. 3

GATA2 and PGR immunohistochemistry in normal cycling endometrium and endometriosis. A Representative H&E, and GATA2 and PGR IHC images from normal endometrium in proliferative or secretory phase, and in endometriosis. B Percent GATA2 positive nuclei in proliferative and secretory endometrium, and in endometriosis. All IHCs are DAB with hematoxylin counterstain. NS = not significant, *p < 0.05, **p < 0.005, ****p < 0.00005. Scale bar = 50 microns

Fig. 4

Correlation between GATA2 and PGR IHC expression in normal endometrium and endometriosis. A-B Plot of percent nuclei positive for GATA2 and PGR in all analyzed cases of normal endometrium and endometriosis within (A) glandular and (B) stromal cells. C Diagram of GATA2 and PGR expression in normal cycling endometrium contrasted with endometriosis and EAH/EIN. In normal cycling endometrium GATA2 levels are low in secretory phase and high in proliferative phase, while PGR levels are high throughout but highest in proliferative phase. GATA2 levels are lower in inactive and hormone treated endometrium, similar to secretory phrase endometrium. In all conditions, GATA2 remains in a positive feedback loop with PGR while also contributing to PGR gene target transcription. In endometriosis and EAH/EIN, GATA2 levels in stromal cells are markedly reduced, while PGR levels remain high. In stromal cells, GATA2 no longer forms a positive regulatory loop with PGR, and we hypothesize that reduced GATA2 levels fail to contribute to PGR target gene transcription. EAH/EIN = endometrial atypical hyperplasia/endometrioid intraepithelial neoplasia