['To investigate whether abnormal expression of Musashi-1 occurs in eutopic and ectopic endometria from patients with adenomyosis and whether it is correlated with serum estradiol or progesterone levels.', 'Musashi-1 expression in ectopic and paired eutopic endometrium of patients with adenomyosis (adenomyosis group, 30 cases) and in normal endometrium (control group, 29 cases) was studied with immunohistochemistry, and serum estradiol and progesterone levels in these cases were measured with electrochemiluminescence immunoassay.', 'In all the normal endometrial tissues from control group and paired eutopic and ectopic endometrium of adenomyosis, epithelial and stromal Musashi-1 expression was observed throughout the menstrual cycle. Musashi-1 immunostaining was localized both in the nucleus and cytoplasm. The epithelial cells in normal endometrium showed a significantly higher staining index of Musashi-1 in the proliferative phase than in the secretory phase. The staining index of epithelial Musashi-1 in the ectopic endometrium was significantly higher than in the paired eutopic endometrium and normal endometrium throughout the menstrual cycle. In the secretory phase, the epithelial Musashi-1 immunoreactivity in eutopic endometrium and the stromal Musashi-1 immunoreactivity in ectopic endometrium were significantly higher than those in the normal endometrium. The Musashi-1 expression in the ectopic endometrium of adenomyosis was not correlated with the serum estradiol or progesterone levels.'] Does increased expression of the adult stem cell marker Musashi-1 in the ectopic endometrium of adenomyosis correlate with serum estradiol and progesterone levels?