Development and Clinical Validation of a Blood Test Based on 29-Gene Expression for Early Detection of Colorectal Cancer

A blood test for early detection of colorectal cancer is a valuable tool for testing asymptomatic individuals and reducing colorectal cancer-related mortality. The objective of this study was to develop and validate a novel blood test able to differentiate patients with colorectal cancer and adenomatous polyps (AP) from individuals with a negative colonoscopy. A case-control, multicenter clinical study was designed to collect blood samples from patients referred for colonoscopy or surgery. Predictive algorithms were developed on 75 controls, 61 large AP (LAP) ≥1 cm, and 45 colorectal cancer cases and independently validated on 74 controls, 42 LAP, and 52 colorectal cancer cases (23 stages I-II) as well as on 245 cases including other colorectal findings and diseases other than colorectal cancer. The test is based on a 29-gene panel expressed in peripheral blood mononuclear cells alone or in combination with established plasma tumor markers. The 29-gene algorithm detected colorectal cancer and LAP with a sensitivity of 79.5% and 55.4%, respectively, with 90.0% specificity. Combination with the protein tumor markers carcinoembryonic antigen (CEA) and CYFRA21-2 resulted in a specificity increase (92.2%) with a sensitivity for colorectal cancer and LAP detection of 78.1% and 52.3%, respectively. We report the validation of a novel blood test, Colox®, for the detection of colorectal cancer and LAP based on a 29-gene panel and the CEA and CYFRA21-1 plasma biomarkers. The performance and convenience of this routine blood test provide physicians a useful tool to test average-risk individuals unwilling to undergo upfront colonoscopy. Clin Cancer Res; 22(18); 4604-11. ©2016 AACR.