Expression of Placenta Growth Factor Is Associated with Unfavorable Prognosis of Advanced-Stage Serous Ovarian Cancer

Ovarian cancer is the fourth leading cause of cancer death in women and the most fatal gynecologic malignancy. Placenta growth factor (PGF), a member of the vascular endothelial growth factor, plays an important role in angiogenesis. The overexpression of PGF was observed in several types of cancers, but the clinical significance of PGF in epithelial ovarian cancer (EOC) is still unknown. To explore the prognostic value of PGF among patients with serous EOC, we analyzed the expression of PGF in 89 EOC specimens by immunohistochemistry. The scoring system of immunohistochemistry was based on the staining intensity and the percentage of PGF-positive cells in each EOC tissue. According to the immunohistochemical score, 34 patients with score ≥ 6 were defined as high PGF expression, and other 55 patients were the group with low PGF expression. The prognostic significance of PGF expression was analyzed. EOC patients with higher IHC scores of PGF expression are significantly associated with positive lymphatic invasion and poorer response to chemotherapy. Patients with higher IHC scores of PGF expression had poorer response to chemotherapy and lower overall survival rate. Additionally, the positive lymph node metastasis, advanced TNM stage, and poorer response to chemotherapy were all remarkably correlated to poorer prognosis. In conclusion, patients with higher PGF in EOC tissues were more predisposed to positive lymphatic invasion, poorer response to chemotherapy and unfavorable prognosis of patients with serous EOC. We propose that PGF expression may be predictive of chemoresistance and poor prognosis of serous EOC.