The Comparison of Myometrial Cellular Proliferation and Apoptosis as a Cause of Leiomyoma and the Relationship with Menstrual Cycles and Expression of ER/PR

Song, Eun Seop; Koh, Seung Kwon; Hwang, Tae Sook

Abstract

OBJECTIVE
To know whether leiomyomas come from increased proliferation or from decreased apoptosis of uterine muscular cells, and compare the results with the menstrual cycles and expression of ER/PR.
METHODS
Between Mar. 2003 to Jun. 2003, the authors got 15 leiomyomatous and normal myometrial tissues from the patients who had undergone hysterectomy transabdominally or laparoscopically. As soon as they were excised, these tissues had been sent to the pathologic department to be stained by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) to determine apoptotic index (A.I.), and immunohistochemistry of Ki-67 to do Ki-67 immunoreactivity index (K.I), and ER/PR.
RESULTS
There was no statistically significant difference of A.I. between leiomyoma and normal myometrial tissues But there was a significantly higher Ki-67 immunoreactivity index in leiomyoma rather than normal myometrial tissue. The increase of K.I. in leiomyomas has the reverse correlation with age, but was not statistically correlated with the menstrual cycles. There was no significant different pattern of expressions of ER/PR between in leiomyoma and in normal uterus.
CONCLUSION
The main reason the leiomyomas come from may be increased proliferation instead of decreased apoptosis of leiomyoma cells. Although leiomyomas were known to be influenced by sex hormone, there was no solid evidence of increase of K. I. correlated with menstrual cycle or expression status of ER/PR in leiomyomas. Maybe there are another factors such as age that control the pathogenesis of leiomyoma rather than hormones or their receptors.