Mig-7 expression and vasculogenic mimicry in malignant ovarian tumors.

OBJECTIVES: To investigate the possible association of vasculogenic mimicry (VM), VE-cadherin and MIG-7 expression with clinicopathological features of women with malignant ovarian masses.

MATERIAL AND METHODS: VM was studied with the PAS reaction and VE-cadherin was assessed with immunohistochemistry in 108 women with malignant ovarian tumors. Additionally, quantitative expression of MIG-7 mRNA was performed in 52 ovarian cancers with qRT-PCR.

RESULTS: VM was found in 48/108 cases (44%), more often in higher FIGO stage tumors (83% cases; 40 vs. 8; p = 0.01). High expression of VE-cadherin was present in 37% of all ovarian masses. Ovarian tumors without VM more often expressed low levels of VE-cadherin than tumors where VM was found (37.6% vs.14.6%). No expression or very low expression of MIG-7 mRNA was found in all normal ovarian tissues and in 32 cancer samples. Median RQ of MIG-7 mRNA in tumor samples was higher than in normal ovarian tissue (RQ = 0.29 vs. RQ = 0.05, respectively; p < 0.005) and higher than in non-malignant ovarian masses (0.98 vs. 0.05 respectively; p = 0.03). Expression of MIG-7 mRNA was significantly correlated with VM (p = 0.039). In tumors with PAS-positive structures median RQ MIG-7 mRNA was higher than in tumors with PAS-negative findings (1.89 vs. 0.13 respectively). VE-cadherin expression was more frequently found in tumors where MIG-7 mRNA was present (p = 0.004).

CONCLUSIONS: Vasculogenic mimicry exists in malignant ovarian tumors and advanced clinical stages of malignancy are accompanied by a high incidence of VM formation. MIG-7 mRNA and VE-cadherin expression may serve as additional molecular markers of VM in ovarian malignancies.