Differences In The Angiogenesis Of Benign And Malignant Ovarian Tumors, Demonstrated By Analyses Of Transvaginal Color Doppler Ultrasound, Immunohistochemistry

BACKGROUND: To clarify the differences in angiogenesis between benign and malignant ovarian tumors, the authors examined the immunohistochemical characteristics in both tumor groups. Intratumoral vascularization was observed preoperatively by transvaginal color Doppler ultrasound. METHODS: The authors examined 91 patients with ovarian tumors preoperatively for the presence or absence of intratumoral blood flow and evaluated the blood flow waveforms of tumor vessels in patients showing intratumoral vascularization, using a resistance index (RI) and pulse index(PI). The characteristics of smooth muscle in the vessels of each tumor were immunohistochemically assessed, using monoclonal antibodies againstα-smooth muscle actin (SMA). RESULTS: Intratumoral blood flow was found in 58 of 91 patients (63.7%). The tumors in 30 of these 58 patients were histopathologically benign, and the tumors in 28 were malignant. The vessels of malignant tumors significantly demonstrated poor SMA expression(mean, 73.73±6.08), compared with the vessels of benign tumors (mean, 83.81±7.10)(P < 0.05)。The expression ofα-SMA were lower in the cases of clinical StageⅢ-Ⅳ,with metastasis and lower tumor grades than that of clinical Stage I-Ⅱ,higher tumor grades and without metastasis (P<0.05). The malignant tumors showed a lower RI (mean, 0.45±0.09) compared with benign tumors (mean, 0.68±0.12) (P < 0.05). RI was different among tumors grades and stages (P<0.05). Compared with the PI of benign ovarian tumors, the PI in ovarian cancers was significantly lower (P<0.05)。However, no significant differences were observed of PI in different clinical stages and tumor grades of malignant tumors. There was a significant positive correlation betweenα- SMA , PI and RI( P<0.O5).CONCLUSIONS: In this study, immunohistochemical analysis demonstrated that low resistance to blood flow in vessels within malignant ovarian tumors may be associated with a poorly developed muscular coat in the tumor vessels, compared with that observed in benign tumors. The difference in the angiogenic natures of benign and malignant ovarian tumors showing intratumoral blood flow may thus be correlated with the endothelial cell activity of the tumor vessels. TVS-CDU is of great clinical and practical value in disting benign and malignant ovarian tumors, andα-SMA in the tumor tissues is correlated with the occurrence and development of ovarian cancer.