Tissue factors influencing growth and maintenance of endometriosis.

The unpredictable response of endometriosis to steroids and its recurrence after therapy, led us to hypothesize a possible further control of this pathology by factors other than steroids. The presence of estrogen, progesterone and epidermal growth factor receptors (ER, PR, EGFr) was evaluated using immunohistochemistry before and after therapy with Danazol or a gonadotropin-releasing hormone analogue (GnRHa), Buserelin. EGFr, ER and PR were present in 100% of endometrial specimens, and in 71%, 29% and 49% of endometriotic implants, respectively. Danazol and GnRHa reduced immunohistochemical staining for EGFr antisera in the endometrial and endometriotic specimens. About 21% of endometriosis were EGFr positive and ER negative, suggesting a potential role of epidermal growth factor in growth and maintenance of endometrial ectopia.