Elevated expression of estramustine binding protein (EMBP) in prostatic intraepithelial neoplasia (PIN) compared with malignant and benign prostatic epithelia.

The expression of estramustine-binding protein (EMBP) was studied immunohistochemically in whole-mount prostate sections. Specimens were taken from the prostates of 15 patients who had undergone total prostatectomy due to localized (TOd-T2 NO MO) prostatic cancer (PC). Almost all the examined whole-mount sections displayed areas with prostatic intraepithelial neoplasia (PIN). PIN is regarded as the main precursor of invasive PC. High- and low-grade PIN expressed EMBP. The average positively stained areas accounted for averages of 69.2% and 48.7%, respectively. High-grade PIN contained the highest EMBP levels of all the investigated (benign and malignant) epithelia, followed by moderately differentiated PC. With regard to areas with PC, the highest levels of EMBP expression (61.3%) were observed in moderately differentiated PC; poorly differentiated PC came second. Of all the examined epithelia, EMBP levels were lowest in well-differentiated PC (25.8%). Normal prostatic epithelia and hyperplasia were characterized by low EMBP expression, although somewhat higher than well-differentiated PC. A moderate expression (45%) was observed in the seminal vesicles. According to these results, EMBP was expressed mainly in the diseased peripheral zone (PZ), where PIN and prostatic cancer have their highest prevalence.