BETA-ENDORPHIN EXPRESSION IN GROSS CYSTIC BREAST DISEASE

Opioid peptides have a variety of pathophysiologic actions, playing a novel important role in human breast cancer. The expression of beta-en dorphin was studied in 84 human breast cyst fluids-from gross cystic b reast disease-affected patients. The concentration of beta-endorphin i n pooled breast cyst fluids was over four-fold higher than in respecti ve plasma with a significant increase in the mean value of the 'metabo lically active' apocrine cysts when compared with flattened cysts (P < 0.001). The higher levels of Type I cyst suggest de novo mammary synt hesis of endogenous opioid peptides and could represent an altered exp ression of biosynthetic activity of apocrine breast cells, providing a possible explanation on functional changes of gross cysts, on the mec hanism of their formation and a perspective relationship to breast can cer risk.