Association of Ovarian Malignancy with Expression of Platelet-derived Endothelial Cell Growth Factor

Background: At the present time, the pathogenesis of ovarian cancer remains poorly understood, with invasive diagnosis and ineffective treatment for women with the disease. Despite scientific and medical advances in oncology, the overall 5-year survival rate of 30% for ovarian cancer patients has not changed in 20 years. An understanding of the angiogenic process as it occurs in ovarian cancer would not only increase our knowledge of the pathogenesis of this cancer but also might offer novel opportunities for therapeutic intervention.

Purpose: Our aim was to study the expression of messenger RNA (mRNA) coding for four putative angiogenic factors in normal ovaries and benign and malignant ovarian tumors: platelet-derived endothelial cell growth factor (thymidine phosphorylase), vascular endothelial growth factor, basic fibroblast growth factor, and transforming growth factor-beta 1.

Methods: Four normal ovaries and 25 tumors (seven benign, one of borderline malignancy, and 17 malignant) were collected from 29 patients during elective oophorectomy. The site of sampling (areas of high-velocity blood flow) was directed by transvaginal color Doppler imaging performed within 24 hours of the surgery. Increased blood flow within the tissues was demonstrated by the presence of color (i.e., the velocity was > 7 cm/s) and, together with a pulsatile index of less than 1.0, constituted a positive scanning result. In scan-positive tissues, the area of maximum blood flow was chosen. In scan-negative tissues, a solid area was chosen in complex lesions, or the cyst wall was chosen in simple lesions. Ovarian RNA was subsequently extracted from areas of high-velocity flow (i.e., tissues with a positive scanning result) or from solid areas or septa in tissues with a negative scanning result. A ribonuclease protection assay was used to assess the expression of mRNA coding for the four angiogenic factors.

Results: Two normal ovaries (containing a corpus luteum) and one benign and 17 malignant tumors (plus the borderline) gave a positive scanning result. There was a significant difference between the expression of mRNA for platelet-derived endothelial cell growth factor between scan-positive and scan-negative tissues (P < .001) and between benign and malignant tumors (P < .001).

Conclusions: Areas of high blood velocity in ovarian tumors are associated with increased expression of platelet-derived endothelial cell growth factor.

Implications: Drugs that affect the angiogenic activity of platelet-derived endothelial cell growth factor offer a potential route for therapeutic intervention.