Expression and localisation of osteopontin and prominin-1 (CD133) in patients with endometriosis

In this study, we investigated the expression and localisation of the proteins,osteopontin (OPN) and prominin-1 (CD133), as well as the plasma OPN levels in theendometrium of patients with endometriosis. Samples of ectopic endometrioticlesions and normal endometrium were obtained from 31 women with endometriosis and28 healthy control subjects. The mRNA and protein expression of OPN and CD133 wasanalysed by real‑time RT-PCR and immunohistochemistry. The plasma levels of OPNwere determined by ELISA. Our results revealed that OPN mRNA and proteinexpression, as well as its release in the blood, was significantly increased inthe endometriotic lesions in comparison to normal tissue. Although the presenceof CD133+ cells was detected in the normal endometrium, as well as in theendometriosis specimens, a significant quantitative variation of this protein wasnot demonstrated in the patients with endometriosis. In conclusion, our dataindicate that OPN is involved in the development of endometriosis by enhancingthe invasiveness, proliferation and survival of endometrial cells in ectopiclesions. CD133 cannot be used as a disease marker for endometriosis, although an involvement of this protein in the pathogenesis of endometriosis cannot beexcluded.