The major purposes of the present study were to examine patient plasma Ang2 level change during the 1st 8 weeks after the standard open thoracic surgery for NSCLC, and to assess the effect of Ang2 in the postoperative plasmas on endothelial cell tube formation in vitro, thus providing evidence to evaluate the appropriateness of using anti-Ang2 cancer therapy in the postoperative adjuvant setting. Here, ANGPT2 is linked to cancer.