RESUMEN
OBJECTIVE: To compare the expression of estrogen receptor α (ERα) and progesterone receptor (PR) in myometrium and leiomyomata tissue, and to correlate their expression with symptoms of uterine leiomyomata. METHODS: In a cross-sectional study, intraoperative biopsy samples of leiomyomata and adjacent myometrial specimens were obtained from premenopausal women with uterine leiomyomata treated at a center in Nigeria between September 2013 and August 2014. Immunohistochemistry for ERα and PR expression was performed on the samples. The immunoscores of both receptors were correlated with the size and symptoms of the leiomyomata. RESULTS: Among 60 pairs of samples, leiomyomata had a higher mean expression of ERα (H-score 193.42±64.55 vs 153.29±69.13; P=0.01) and PR (214.86±66.56 vs 171.53±63.53; P<0.001) than did myometrial tissues. The tumor diameter correlated negatively with the immunoscores of both receptors irrespective of age, parity, and body mass index, but this was only significant for PR (ρ=-0.44; P<0.001). Downregulation of PR on leiomyomata was predicted to occur at a diameter of 11cm. Menorrhagia, dysmenorrhea, and infertility occurred independently of steroid-receptor expression. CONCLUSION: Leiomyomata seem to depend on steroid hormones, but only during early tumor development. This could have implications for the selection of patients for medical management, especially with steroid-receptor modulators.