High intraepithelial expression of estrogen and progesterone receptors in the transformation zone of the uterine cervix

Objective Because sex hormones may be involved in tumor initiation and progression, we analyzed the presence of hormone receptors in the transformation zone of the uterine cervix where the majority of human papillomavirus infections and associated (pre)neoplastic lesions develop. Study design By using 23 total hysterectomy samples from young women who underwent surgery for noncervical benign uterine disease, we analyzed, by immunohistologic techniques, the in situ expression of estrogen (E2-R) and progesterone (P4-R) receptors in the transformation zone and ectocervix of the same women. Results The expression of estrogen receptors and progesterone receptors is significantly higher in the transformation zone compared with the ectocervix. Immunohistochemical localization indicated that hormone receptor-positive cells are mainly observed in (para)basal and intermediate cell layers in both the transformation zone and ectocervical epithelium. When transformation zone samples were segregated into epithelial tissues with a predominantly mature (7/23 samples) or immature (16/23 samples) squamous metaplasia, only biopsy specimens with immature squamous metaplasia showed a significantly higher density of hormone receptor-positive cells compared with ectocervical epithelium (P<.01). Conclusion Our results suggest that the cervical transformation zone may be at increased risk of the development of cancer because of a high sensitivity to sex hormone regulation.