OBJECTIVETo investigate the expression of the anti-oncogene ARHI in the endometriotic tissue and explore its clinical significance.

METHODSA semiquantitative analysis of the expression of ARHI mRNA and protein in the ectopic and eutopic endometrium of women with endometriosis was conducted using RT-PCR and Western blotting in comparison with that in the endometrium of women without endometriosis. Immunohistochemistry and in situ hybridization were performed for semi qualitative analysis and localization of ARHI expression.

RESULTSThe expression levels of ARHI mRNA and protein differed significantly between the groups. ARHI was expressed at significantly higher levels in ectopic endometrium than in eutopic and normal endometrium (P<0.005), but showed no significant difference between the latter two tissues (Pgt;0.05). The positivity rate ARHI DNA was 97.3% in the endometrium of women without endometriosis, 100% in the ectopic endometrium and 93.8% in the eutopic endometrium of women with endometriosis. immunohistochemistry showed an ARHI positivity of 93.2% in the endometrium of women without endometriosis, 100% in the ectopic endometrium and 92.3% in the eutopic endometrium of women with endometriosis. The expression patterns of ARHI DNA and protein were consistent. Immunohistochemistry in 5 cases of malignant endometriosis showed negative ARHI expression in 4 cases and weak positivity in 1 case.

CONCLUSIONARHI expressions are present in the endometrium and up-regulated in ectopic endometrium, whereas in the ectopic endometrium of patients with malignant endometriosis its expression is often negative, suggesting a role of ARHI in infertility and tumorigenesis of endometriosis.