KDR and non-small cell lung carcinoma: In this study we evaluated (1) changes in CECs, defined as CD34bright/CD45−/(VEGFR2+), and HPCs, defined as CD34bright/CD45dim/(CD133+), in NSCLC patients treated with anti-angiogenic therapy with sorafenib plus erlotinib (SO/ER); (2) we investigated the specificity of these changes by comparing these with a control group of patients receiving bevacizumab plus erlotinib (BV/ER) or monotherapy erlotinib, and (3) we correlated the changes of the biomarkers with treatment response in the SO/ER patient group.