Selecting Patients With Stage Ii/Iii Colorectal Cancer For 5-Fluorouracil-Based Adjuvant Chemotherapy Using Proteomic Analysis.

708Background: 5-fluorouracil (5-FU) is a common adjuvant treatment for stage III and high-risk stage II colorectal cancer (CRC). However, about 20% of patients relapse within 48 months of treatment with 5-FU, even when combined with oxaliplatin. To improve patient selection, tumor biomarkers that predict sensitivity to 5-FU have been proposed. These include proteins involved in 5-FU activation or metabolism such as uridine-cytidine kinase 2 (UCK2) and thymidylate synthase (TYMS). We used multiplexed mass spectrometry to evaluate the utility these biomarkers in the archived tumor samples of patients with stage II/III CRC. Methods: Tumor samples were from 143 patients with stage II/III CRC who received adjuvant 5-FU, folinic acid, and oxaliplatin during 2000-2014; 83% of patients received 12 cycles and the others received ≤ 11 cycles. Tumor cells were microdissected and solubilized, and 67 candidate biomarkers were quantitated using mass spectrometry. Overall survival (OS) and relapse-free survival (RFS) w...