Abstract 3937: Minimally invasive colorectal resection (MICR) is associated with elevated plasma levels of Urokinase-type Plasminogen Activator-1 (uPA) from 2nd to 6th week after surgery which may promote tumor growth and metastasis

Introduction: Urokinase-type Plasminogen Activator-1 (uPA) is a secreted protease that activates Plasminogen to form Plasmin. uPA binds to the widely expressed uPA receptor (uPAR); uPA-uPAR complexes can be inhibited by Serpin E1/ Plasminogen activator inhibitor-1(PAI-1). Active plasmin catalyzes many physiopathological processes requiring basement membrane (BM) and/or extracellular matrix (ECM) remodeling. uPA together with uPAR and PAI-1 plays a wide role in regulating tumor cell proliferation, adhesion, migration, intravasation and metastasis. uPA and uPAR promote immune cell activation at sites of matrix remodeling during wound healing. uPA directly or via plasmin leads to activation of various angiogenic growth factors including VEGF and IGF. Over expression of uPA has been documented in several cancers including colorectal cancer (CRC) and high tissue levels correlated with a poor prognosis. The impact of minimally invasive colorectal resection (MICR) for CRC on plasma uPA levels is unknown. This study's aim was to measure plasma uPA levels during the first postoperative (postop) month. Method: CRC patients (pts) undergoing MICR who were enrolled in an IRB approved data/plasma bank for whom adequate plasma was available were eligible. Clinical, demographic and pathological data were prospectively collected. Blood samples were collected PreOp and on postoperative day (POD) 1, 3 and at least 1 late timepoint (between POD7-41). Late samples were bundled into 7 day time blocks and considered as single time points. Total uPA levels were analyzed in duplicate via ELISA and the results reported as mean and ±SD. The Wilcoxon paired t-test was used for analysis (significance, p