BMC Cancer 2009, 9:421 http://www.biomedcentral.com/1471-2407/9/421 Conclusion In conclusion, to our knowledge, this is the first study investigating the initial changes in plasma VEGF levels for the prediction of insufficient response to therapy and dis- ease progression in advanced NSCLC patients during first- line chemotherapy. Our results clearly show the relevance of circulating VEGF levels in differentiating responders from non-responders to therapy and in predicting disease progression. In future, such analyses could also be used for monitoring of tumor recurrence. Conflicts of interests The authors declare that they have no competing interests. Authors' contributions SK carried out the experimental work, participated in study design and manuscript preparation. RG participated in study design and manuscript drafting. VS participated in statistical analysis. ACB helped in study design and coordination. 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