c-kit/CD 117 positive cells in the myometrium of pregnant women and those with uterine endometriosis

PURPOSE: Abnormal myometrial motility may play a role in the pathogenesis of endometriosis. Uterine contractility is a major contribution to labour. Myometrial motility might be controlled by CD 117-positive uterine smooth muscle cells. METHODS: Myometrial tissues from 8 cases with uterine endometriosis, 9 pregnant uteri (31.1 ± 8.7 weeks of gestation), 10 cases from non-pregnant pre-menopausal and 9 cases from post-menopausal women were immunohistochemically evaluated using a polyclonal antibody against c-kit/CD 117. The number of CD 117 positive cells was counted within 10 microscopic high power fields (× 400) and compared with the clinical diagnoses. RESULTS: Overall, a mean number of 15.7 (range 0-43) CD 117-positive cells within the myometrium was seen. Significant highest count occurred in the myometrium of non-pregnant pre-menopausal women without uterine endometriosis (30.78 ± 9.52), followed by post-menopausal women (15.5 ± 8.37) and those with uterine endometriosis (9.98 ± 4.9; p ≤ 0.01). The lowest count of CD 117-positive cells was seen in pregnant uteri (4.09 ± 2.33; p < 0.001). CONCLUSIONS: The lowest count of CD 117-positive cells was seen in the myometrium of pregnant women suggesting a role of preventing premature uterine contractility. There is no increase of CD 117-positive cells in the myometrium of women affected by uterine endometriosis.