Expression of VEGF, VEGFR, EGFR, COX-2 and MVD in cervical carcinoma, in relation with the response to radio-chemotherapy

Abstract

Introduction: Despite the improvement in the treatment results due to modern irradiation techniques and to the association of chemo-radiotherapy, cervical cancer remains an unsolved problem of oncology both due to the increased rate of local failures and of the distant metastasis. Efforts to implement new therapeutic strategies in order to obtain better results in patients with cervical cancer appear justified. Neovascularization is an important step in the tumor progression and the therapeutic targeting of the tumor blood vessels appears to be a good strategy to follow in the anti-cancer treatment. Thus, even in an incipient phase of the clinical research process, the combination between the anti-angiogenic aimed therapies and the current radio-chemotherapy seems to represent a new, feasible and promising approach. The aim of the present study was to determine the prognostic and/or predictive value of some biological markers of tumor angiogenesis and of their implication in increasing the efficacy of current treatments for this cancer.

Materials and methods: So far, 54 women were included in a prospective trial: 44 having an advanced cervical carcinoma and 10 healthy women, as controls. A tumor biopsy and a blood sample were obtained from each patient before the start of therapy. The density of microvascularization was assessed using CD34 monoclonal antibody (hot spot technique), the expression of angiogenic factors VEGFR, EGFR and COX-2 were determined in tumor biopsies by specific immunohistochemistry techniques, using primary antibodies anti-EGFR, anti-VEGF and anti-COX-2 respectively. The quantitative polymerase chain reaction (Real Time PCR) was employed for assessing the expression level of the genes involved. Serum VEGF was determined by quantitative ELISA technique.

Results: Among the studied clinical and molecular factors, we found to be predictive for the type of response the following factors: tumor size at diagnosis (p=0.01), VEGFR2 expression (p=0.02) and a tendency to significance for patients' age (p=0.06). From the large panel of studied markers it was observed correlation between MVD expression with stromal COX-2 (p=0.01) and a tendency with epithelial COX-2 (p=0.06). Stromal COX-2 has higher correlation with VEGFR2 (p=0.01) and MVD (p=0.01) and also has a lower correlation with tumor size (p=0.08).

Conclusions: Univariate analysis demonstrates that the response to radio-chemotherapy in cervical cancer is related to a set of clinical and molecular factors as: the tumor size, the expression of VEGFR2 as mRNA level and the patients' age. Unfortunately, the multivariate analysis by logistic model selects only VEGFR2 expression for prediction of tumor response. The interrelations between the different biomarkers demonstrate the complexity of the tumor progression process and the necessity of further studies to identify new therapeutic targets.