Prognostic significance of vascular endothelial growth factor, tumor necrosis, and mitotic activity index in malignant pleural mesothelioma.

Objectives: Tumor growth and metastasis are angiogenesis-dependent events, and several prognostic factors have been determined in malignant mesothelioma. In this study, we investigated the prognostic significance of vascular endothelial growth factor (VEGF), tumor necrosis (TN), and mitotic activity index (MAI) in malignant mesothelioma. For the first time (to our knowledge), we also demonstrated the association between VEGF staining, TN, and MAI in malignant mesothelioma.

Methods: Decortication and VATS materials of 40 patients were investigated. The routinely processed formalin-fixed, paraffin-embedded, hematoxylin-eosin-stained tumor sections that had been used for the original diagnostic purposes were retrieved. Hematoxylin-eosin sections were selected for VEGF immunostaining, TN, and mitotic count. Clinicopathologic data, stage of disease, and survival of patients were all determined. The correlations between variables were evaluated by Spearman rank correlation test. Both univariate analysis using the log-rank test and multivariate analysis using Cox regression model were performed for survival analysis.

Results: There was a significant correlation between VEGF staining and TN (r = 0.42, p = 0.006). In univariate analysis, both VEGF staining (p = 0.0002) and TN (p = 0.0055) showed significant correlation with short survival. Also, there was a positive correlation between VEGF and tumor stage (p = 0.046). In multivariate analysis, only VEGF was determined as an independent prognostic factor in malignant mesothelioma (p = 0.001). There was no association between MAI and survival (p = 0.504).

Conclusions: VEGF, known as an important angiogenic peptide, is an independent prognostic factor in malignant pleural mesothelioma. TN stimulates angiogenesis, and we observed a significant correlation between VEGF and TN. However, further studies are needed to evaluate the prognostic significance of angiogenic properties in malignant mesothelioma.