Comparative analysis of serum and tumor vascular endothelial growth factor, insulin-like growth factor 1, matrix metalloproteinase 7 levels in patients with ovarian cancer

Abstract

Aim: To perform a comparative analysis with simultaneous measurement of vascular endothelial growth factor (VEGF), insulin-like growth factor 1 (IGF1) and matrix metalloproteinase 7 (MMP7) in serum samples taken from healthy women and ovarian cancer patients; to perform association of these markers with their expression in primary tumors depending on clinical, morphological and biochemical characteristics of the disease and its prognosis. Materials and methods: We assessed 54 treatment-naïve patients with ovarian cancer aged from 23 to 74 years (mean ± SD, 53.2 ± 1.9), being at various FIGO stages of the disease. The control group consisted of 120 healthy women of matched age and reproductive status, in whom serum biomarker levels were studied. Patient survival was assessed by the Kaplan-Meier method, with survival curves compared with log-rank test. All analyses were done with “STATISTICA” and SPSS software. Results: Serum VEGF levels in ovarian cancer patients were significantly (p < 0.0001) higher compared those in the control. The most informative cut-off values differentiating the groups studied were serum VEGF values of < 350 pg/ml (median value in the control) and > 505 pg/ml (upper quartile in the control). With 505 pg/ml taken as a threshold, the test had sensitivity of 79.6% and specificity of 75%. Another cut-off value of serum VEGF level between the patients with ovarian cancer and the control group (510 pg/ml) was derived from ROC curves and 75% sensitivity and 78.2% specificity. No acceptable cut-off value for serum IGF1 to differentiate between the patients with ovarian cancer and the controls could be obtained from the ROC curves. Serum MMP7 levels in the patients with ovarian cancer were significantly higher than those in the control group (Mann-Whitney test p < 0.0001). With ROC curves, the best sensitivity to specificity ratio for MMP7 value of 4.6 ng/ml was obtained to differentiate between the patients with ovarian cancer and the controls (sensitivity 83.3%, and specificity 81%). The variance analysis did not reveal any association between serum VEGF, IGF1 and MMP7 and age of patients with ovarian cancer, tumor histology, concomitant somatic and gynecological diseases, and CA-125 levels. Serum VEGF and IGF1 levels did not correlate with the stage of ovarian cancer, in contrast to MMP7, whose levels were significantly higher in stages IIIc–IV. The median VEGF level significantly increased as the degree of differentiation decreased from 510 to 622 pg/ml (p < 0.002), while median IGF1, on the contrary, decreased from 219 to 116 pg/ml (p < 0.0001). There was a direct correlation between serum and tumor VEGF levels in ovarian cancer patients (r = 0.65, p < 0.0001). On the contrary, there was an inverse correlation between serum and tumor IGF1 levels (r = -0.68, p < 0.0001). Serum and tumor MMP7 levels remained unrelated to each other. Tumor VEGF, IGF1 and MMP7 content was unrelated to the age of the patients, their reproductive status, presence of concomitant somatic and gynecological diseases, histology of ovarian cancer, and serum CA-125 levels. VEGF levels in the tumor were not associated with the stage of ovarian cancer, but in patients with initial stages Ia and Ib stages MMP7 values significantly lower (2.1 ng/mg protein) compared to those in stages IIIc and IV (6.1 and 4.7 ng/mg protein, respectively, p < 0.05). Similar pattern was noted for IGF1: tumor IGF1 values in the patients with stages Ia–Ib were significantly lower (0.5 ng/mg protein) than those with stages IIIc–IV (median, 1.3–1.4 ng/mg protein). A significant increase in both serum and tumor VEGF levels was detected in the patients with ovarian cancer with decreased degree of differentiation. On the contrary, tumor IGF1 levels, but not serum ones, were significantly increased from 0.6 to 1.4 ng/ml in the patients with poorly differentiated ovarian cancer. MMP7 tumor expression did not depend on the degree of its differentiation. Serum VEGF levels above 700 pg/ml and tumor levels of above 590 ng/mg protein should be considered as unfavorable prognostic factors in patients with ovarian cancer.

Keywords

• ovarian cancer
• vascular endothelial growth factor
• insulin-like growth factor 1
• matrix metalloproteinase 7