Role of oestrogen receptor-α and -β in bladder tissue of patients with a clinical diagnosis of benign prostatic hyperplasia.

OBJECTIVES: To study the differential expression of oestrogen receptor (ER) subtypes in human urinary bladder tissue using immunohistochemistry (IHC) methods and to explore their correlation with various measures of lower urinary tract symptoms (LUTS).

METHODS: In this prospective case-control study, the case group comprised 34 patients with bothersome LUTS who underwent transurethral resection of prostate (TURP), while the control group comprised 19 age-matched, otherwise healthy patients who underwent cystoscopy to investigate microscopic haematuria. Cystoscopy and bladder biopsy were performed in both groups. IHC evaluation of biopsy specimens was carried out for ER subtypes (ER-α and ER-β) and for Ki 67 in semi-quantitative fashion. Correlations of receptors with various measures of benign prostatic hyperplasia (BPH)/LUTS were also assessed.

RESULTS: Expression of ER-α (in both epithelial and stromas cells) was statistically significantly greater in the case group than in the control group, but ER-β expression was not significantly different between the groups. Ki 67 expression was also significantly greater in the case group. Comparison of clinical variables according to receptor status showed that International Prostate Symptom Score (IPSS), post-void residual urine volume (PVR) and prostate volume were significantly associated with epithelial and stromal ER-α; however, ER-β was associated only with PVR.

CONCLUSION: We found significant correlation between bladder ER levels (specifically ER-α) and various clinical measures of BPH. We conclude that ER-α is the key mediator that could be responsible for various clinical measures of BPH/LUTS.