Comparison of RCAS1 and metallothionein expression and the presence and activity of immune cells in human ovarian and abdominal wall endometriomas

Metallothionein, RCAS1, CD25, CD69, CD56, CD16, CD68 antigen expression was assessed by immunohistochemistry in ovarian and scar endometriomas tissue samples which were obtained from 33 patients. The secretory endometrium was used as a control group (15 patients).The lowest metallothionein expression was revealed in ovarian endometriomas in comparison to scar endometriomas and to the control group. RCAS1 expression was at the highest level in the secretory endometrium and it was at comparable levels in ovarian and scar endometriomas. Similarly, the number of CD56-positive cells was lower in scar and ovarian endometriomas than in the secretory endometrium. The highest number of macrophages was found in ovarian endometriomas. RCAS1-positive macrophages were observed only in ovarian endometriomas. CD25 and CD69 antigen expression was higher in scar and ovarian endometriomas than in the control group.The expression of RCAS1 and metallothionein by endometrial cells may favor the persistence of these cells in ectopic localization both in scar following cesarean section and in ovarian endometriosis.The ovary is the most common location of the ectopic endometrium occurrence in the pelvic genital organs. Endometriosis is also found outside the genital tract. The cesarean scar was the most common site of extragenital endometriosis [1]. It was suggested in the 1950s that endometrioma occurring in a cesarean scar might result from specific endometrial changes depending on the pregnancy development [2]. Ovarian endometriosis, however, was thought to be associated with retrograde menstruation [3]. The aforementioned two hypotheses in combination with the current opinion indicating that the endometrial tissue acquires a secondary gestagen resistance [4] indicates the natural ability of endometrial cells to coexist with adjacent activated immune cytotoxic cells within the decidua. This phenomenon is secondary to the participation of endometrial cells in reproduction and enables the