Estrogen & Progesterone Receptor Profiles in Endometrial Simple Hyperplasia – Comprehensive Study Notes

Endometrial hyperplasia (EH) constitutes a spectrum of lesions ranging from mild, reversible proliferation to precancerous conditions.
- Four WHO diagnostic categories:
- Simple hyperplasia (SH)
- Complex hyperplasia (CH)
- Simple atypical hyperplasia (SAH)
- Complex atypical hyperplasia (CAH)
SH is the most common gynaecologic disorder manifesting as irregular vaginal bleeding.
Normal cyclic endometrial changes are tightly regulated by steroid hormones:
- Estrogen ➔ stimulates proliferation of both glands & stroma.
- Progesterone ➔ converts proliferative endometrium to secretory phase & induces stromal decidualisation.
- Biological activity depends on hormone-receptor interaction; thus quantity/function of estrogen receptors (ER) & progesterone receptors (PR) is critical.
Previous studies on ER/PR expression in EH yielded conflicting data:
- Sánchez et al.: no difference in ER-positive cell density between normal endometrium & SH/CH.
- Teleman et al.: high ER & PR in SH/CH but significant decrease in atypical hyperplasia.
- Antunes et al.: in endometrial polyps, only stromal ER differed between benign & pre-malignant/malignant groups.
- Age-related receptor changes reported (e.g., loss of PR with increasing age in carcinoma), yet no age-focused SH study existed.

Determine ER & PR expression patterns in SH versus normal proliferative endometrium (NPE).
Evaluate whether expression differs between:
- Glandular epithelium vs. stromal compartment.
- Child-bearing age group vs. perimenopausal group.
Provide mechanistic insight & therapeutic implications for SH pathogenesis.

Archived formalin-fixed, paraffin-embedded tissues, $n = 77$ .
- SH cases: $n = 50$
- Child-bearing age (22–39 yr): $n = 30$
- Perimenopausal: $n = 20$
- NPE controls: $n = 27$ (patients with uterine leiomyoma)
- Child-bearing: $n = 10$
- Perimenopausal: $n = 17$
Inclusion criteria:
- Diagnoses based on International Society of Gynecological Pathologists & WHO criteria.
- No steroid-hormone therapy within $3$ months.
- Absence of other uterine lesions.

Sectioning: $4\,\mu m$ thick slices from paraffin blocks.
Immunohistochemistry (IHC):
- Antigen retrieval: citrate buffer $15$ min.
- Block endogenous peroxidase with $3\%$ $H<em>2O</em>2$ in methanol, $10$ min.
- Primary antibodies: anti-ER, anti-PR; incubation overnight at $4^{\circ}C$ .
- Detection: Elivision Plus kit; DAB chromogen; hematoxylin counterstain.
- Positive control: breast carcinoma sections (known ER/PR positive).
- Negative control: omission of primary antibody.
Scoring:
- Nuclear brown granules counted separately in glands & stroma.
- Positivity threshold: $\ge 10\%$ of cells.

Tests applied:
- Kolmogorov–Smirnov for normality.
- Levene for homogeneity of variance.
- $\chi^2$ test & Mann-Whitney-U for group comparisons.
Significance level: $P < 0.05$ (two-tailed).

Overall ER expression
- Glandular epithelium: SH $94.0\%$ vs. NPE $92.6\%$ ➔ $P = 0.811$ (ns).
- Stroma: SH $84.0\%$ vs. NPE $22.2\%$ ➔ $P = 0.000$ (highly significant).
Overall PR expression
- Glandular: SH $90.0\%$ vs. NPE $92.6\%$ ➔ $P = 0.706$ (ns).
- Stroma: SH $58.0\%$ vs. NPE $66.7\%$ ➔ $P = 0.457$ (ns).
Age-stratified ER (Table 2 data) a. Child-bearing group
- Glandular ER: SH $96.7\%$ vs. NPE $90.0\%$ ➔ $P = 0.442$ .
- Stromal ER: SH $96.7\%$ vs. NPE $40.0\%$ ➔ $P = 0.000$ .
  b. Perimenopausal group
- Glandular ER: SH $95.0\%$ vs. NPE $94.1\%$ ➔ $P = 0.177$ .
- Stromal ER: SH $65.0\%$ vs. NPE $11.8\%$ ➔ $P = 0.001$ .
Age-stratified PR (Table 3 data) a. Child-bearing group
- Glandular PR: SH $93.3\%$ vs. NPE $90.0\%$ ➔ $P = 1.000$ .
- Stromal PR: SH $66.7\%$ vs. NPE $60.0\%$ ➔ $P = 1.000$ .
  b. Perimenopausal group
- Glandular PR: SH $85.0\%$ vs. NPE $94.1\%$ ➔ $P = 0.609$ .
- Stromal PR: SH $45.0\%$ vs. NPE $70.6\%$ ➔ $P = 0.185$ .

Differential localisation: ER up-regulation is confined to stromal compartment in SH; glandular ER remains comparable to normal.
- Suggests stromal ER may drive paracrine or autocrine signals fostering hyperplastic gland-stroma proliferation.
PR expression shows no significant alteration; therefore progesterone pathway appears less implicated in SH initiation.
- PR induction is often estrogen-dependent; elevated stromal ER without parallel PR up-regulation may indicate receptor uncoupling or post-receptor desensitisation.
Age factor:
- Despite known age-related receptor dynamics in carcinoma, SH shows consistent pattern across reproductive and perimenopausal phases.
- Implies stromal ER-mediated mechanism is age-independent in SH pathogenesis.

High stromal ER positivity advocates consideration of anti-estrogenic strategies (e.g., SERMs or aromatase inhibitors) to treat SH and control irregular bleeding.
Absence of significant PR alteration suggests limited benefit from progestin therapy alone, although clinical efficacy must integrate systemic hormone milieu.

Strengths:
- Separate scoring of glands vs. stroma highlights compartment-specific biology.
- Inclusion of age stratification fills previous research gap.
Limitations:
- Semi-quantitative IHC (\u2265 $10\%$ threshold) lacks intensity weighting; could obscure subtle gradations.
- Sample size modest (especially NPE child-bearing $n=10$ ) ➔ risk of type II error in PR comparisons.
- Serum hormone levels not measured; cannot correlate receptor status with systemic estrogen/progesterone.

Quantitative digital image analysis & H-score to refine receptor density assessment.
Correlate receptor profile with circulating hormone assays and clinical outcomes (e.g., response to anti-estrogen therapy).
Evaluate downstream estrogen-responsive genes and stromal–epithelial crosstalk mediators (e.g., growth factors, cytokines).
Explore molecular alterations (e.g., PTEN, \beta-catenin, EMT markers) in conjunction with ER status to map the full pathogenic network.

Archived tissues used; patient confidentiality maintained.
Findings support hormone-targeted therapy which may reduce need for surgical intervention in SH, improving quality of life.

Raychaudhuri G et al. (2013) – clinicopathological EH study.
Goncharenko VM et al. (2013) – predictive diagnosis.
Marra C et al. (2014) – progesterone therapy response.
Gbelcová H et al. (2015) – PTEN analysis.
Ip PP et al. (2013) – papillary proliferation.
Additional refs: Dznelashvili N (2014); Skrzypczak M (2015); Sánchez LF (2007); Teleman S (1999); Antunes A (2014); Sant’Ana de Almeida EC (2004); Tomica D (2014); Gul A (2010); Senol S (2015); Kostiuchek IN (2011).