Elevated RON protein expression in endometriosis and disease-associated ovarian cancers.

BACKGROUND: Recepteur d'origine nantais (RON) protein expression has been demonstrated to correlate with tumor progression, metastasis, and prognosis, and its mRNA expression increases in deeply infiltrating endometriotic lesions. However, it remains unclear whether RON protein expression also increases in endometriotic lesions, and may be a risk factor of malignant transformation in endometriotic lesions.

METHODS: The protein expression of RON in control (n = 19), eutopic (n = 16), and ectopic (n = 51) endometria, as well as in endometriosis-associated ovarian cancers (EAOC, n = 16) was determined by immunohistochemical (IHC) staining.

RESULTS: Endometriotic lesions expressed low levels of RON protein, but no RON protein expression appeared in matched eutopic or control endometrium. EAOC exhibited high levels of RON protein. The frequency and IHC score of RON protein expression were both significantly higher in EAOC [100.0% (14/14), 5.37 ± 0.74] than those in endometriotic lesions [51.0% (26/51), 2.15 ± 1.12; P = 0.002, 0.001]. Multivariate analysis of covariance only revealed a correlation of RON protein expression and EAOC (P = 0.006), but no correlations of RON protein expression and clinical parameters (P > 0.05).

CONCLUSIONS: These obtained results suggest that increased RON expression might be involved in the pathogenesis of endometriosis and disease-associated ovarian cancers.