Intact and cleaved plasma soluble urokinase receptor in patients with metastatic colorectal cancer treated with oxaliplatin with or without cetuximab

Circulating forms of the urokinase plasminogen activator receptor (uPAR) are associated with prognosis in patients with colorectal cancer. Preclinical studies have shown that uPAR can influence the state of phosphorylation and signalling activity of the epidermal growth factor receptor (EGFR) in a ligand‐independent manner. The purpose of the study was to evaluate whether plasma soluble intact and cleaved uPAR(I‐III)+(II‐III) levels could identify a subpopulation of patients with metastatic colorectal cancer (mCRC) where treatment with cetuximab would have a beneficial effect. Plasma samples were available from 453 patients treated in the NORDIC VII study. Patients were randomized between FLOX and FLOX + cetuximab. The levels of uPAR(I‐III)+(II‐III) were determined by time‐resolved fluorescence immunoassay. We demonstrated that higher baseline plasma uPAR(I‐III)+(II‐III) levels were significantly associated with shorter progression‐free survival (PFS) (HR = 1.30, 1.14–1.48, p = 0.0001) and overall survival (OS) (HR = 1.75, 1.52–2.02, p