Diagnostic and Prognostic Performance of Serum Vascular Endothelial Growth Factor, Vascular Endothelial Growth Factor Receptor 2, and Osteopontin for Gastrointestinal Cancers

Background: Biomarkers for early diagnosis and follow-up of cancers are still underutilized in clinical management. Thus, seeking new biomarkers with better sensitivity and specificity is still a challenge. VEGF, VEGFR2, and OPN are newly emerging biomarkers with clinical potential. Methods: ELISA was used to analyze serum VEGF, VEGFR2, and OPN from 75 gastrointestinal cancer patients and 75 control subjects. The correlation of pre-operative serum VEGF, VEGFR2, and OPN levels with CEA, Ki-67 as well as clinical features (age, gender, tumor size, TNM stage, tumor stage, lymph node involvement, metastasis, and histological grading) in these patients. Results: The pre-operative and post-operative serum VEGF and VEGFR2 levels and the post-operative OPN level in patients were significantly higher than in controls (p = 0.000, for all mentioned). The post-operative VEGF and OPN levels were significantly higher than that of pre-operative (p = 0.000 and 0.007, respectively). There was no correlation between pre-operative serum VEGF, VEGFR2, and OPN levels and serum CEA concentration. The pre-operative serum VEGF level was significantly correlated with the tumor Ki-67 scores; however, there was no correlation between serum VEGFR2 and OPN and Ki-67 scores. Univariate logistic regression analysis revealed that serum VEGF level was significantly higher in patients with advanced TNM (III - IV) stage and with lymph node involvement than in patients with low TNM stage (I - II) and with no lymph node involvement. High OPN level was correlated with metastasis. Multivariate logistic regression analysis results showed that serum VEGF and VEGFR2 were the two most important factors for the diagnosis of gastrointestinal cancers in this study (p = 0.000, for both). Combinatorial analysis of the biomarkers improved the performance of the assays. Conclusions: Serum VEGF and VEGFR2 are potential biomarkers for the diagnosis and prognosis evaluation of gastrointestinal cancers, while serum OPN is a potential biomarker for the prognostication of gastrointestinal cancers.