Aim: It has been suggested that colorectal neoplasms with or without microsatellite instability (MSI) can stimulate angiogenesis in different ways. The vascular endothelial growth factor (VEGF) system is essential for the angiogenetic process and the growth of malignant tumours. The aim of this study was to analyse the relationship between serum VEGF-A and the MSI status of patients with colorectal cancer (CRC).
Method: In the study, 249 patients with CRC were divided into a test cohort of 83 patients and a validation cohort of 166. MSI was determined using immunohistochemistry. Tumours lacking protein expression of any of the four mismatch repair genes (MLH1, PMS2, MSH2 or MSH6) were labelled as high MSI. The rest were considered to be microsatellite stable (MSS). The serum VEGF-A analyses were performed by ELISA.
Results: The tumours of 15 patients in the test cohort and 27 in the validation cohort were classified as MSI. In the test cohort, patients with an MSI tumour had a significantly higher median serum VEGF-A concentration [617 pg/ml (95% CI 445-863)], compared with patients with an MSS tumour, [317 pg/ml (95% CI 224-386)], P = 0.01. A similar relationship was confirmed in the validation cohort, P = 0.04.
Conclusion: This study provides some evidence to suggest that patients with an MSI tumour have higher serum VEGF-A levels than patients with an MSS tumour. If further validated, these findings could be of importance when considering the effects of anti-VEGF-A treatment.
© 2011 The Authors. Colorectal Disease © 2011 The Association of Coloproctology of Great Britain and Ireland.