Deficient Expression of Tumor Necrosis Factor Receptor Type 2 in the Endometrium of Women with Endometriosis

Problem: Tumor necrosis factor‐α (TNF‐α) is secreted mainly during the menstrual phase and has been suggested to play a role in induction of apoptosis in endometrial cells and menstrual shedding. TNF‐α receptor type 2 (TNF‐RII) is believed to play a central role in TNFα‐mediated cytotoxic, mitogenic, anti‐proliferative and apoptotic effects. The aim of this study was to assess whether TNF‐RII maybe expressed differentially in the endometrium of women with different degrees of endometriosis. Method of study: TNF‐RII expression in the endometrial tissue of women with and without endometriosis was investigated by immunohistochemical techniques and in situ hybridization. Results: In histological sections, we observed TNF‐RII mRNA and the corresponding protein localized mainly in endometrial glandular cells, with only very faint immunostaining in the surrounding stromal cells. Statistical analysis of our data showed a significant decrease in protein and mRNA expression of TNF‐RII in endometrial glandular cells of patients with stages I and II endometriosis compared to normal subjects. TNF‐RII expression was also found to decrease significantly in the secretory phase of the menstrual cycle in women with early endometriosis stages (I and II). Conclusions: In view of the relevant role of TNF‐RII in the modulation of the inflammatory and the proapoptotic effects of TNFα, deficient expression of TNF‐RII mRNA in the endometrium of women at the earliest stages of endometriosis may play a significant role in the pathophysiology of this disease.