The Great Lakes New England Clinical Validation Center (GLNE CVC), a Clinical Validation Consortium component of the Early Detection Research Network (EDRN) is a highly collaborative group of investigators whose aims to validate biomarkers for the early detection and risk assessment of cancers of the gastrointestinal tract. In this fifth competitive application, the GLNE continues to test the overall hypothesis that a panel of circulating and stool based biomarkers will increase the adherence to colorectal screening and in doing so reduce mortality caused by colorectal cancers. Based on the rising incidence of colorectal cancer (CRC) among adults age <50 in the US, and the low compliance and high mortality in underserved populations, increased emphasis is placed on these populations. The GLNE also proposes to continue its ongoing support of EDRN discovery priorities. We propose to address the following aims: (1) Primary Aim To expand and renew the archive of appropriately preserved stool, serum, plasma, urine, tissue and DNA biospecimens to be used by EDRN investigators for current and future validation and biomarker discovery research with expanded inclusion of subjects with early-onset CRC and underserved populations. This will allow assessment of the utility of individual stool-based, and serum-based biomarkers and biomarker panels for discriminating between individuals without neoplasia (subjects both at average and higher risk for developing colon cancer), and those with colon cancer or screen-relevant neoplasia (cancer plus advanced adenoma), and construction of panels of markers to discriminate between these groups. (2) To perform validation trials of promising biomarkers discovered by EDRN investigators, external collaborating institutions and collaborating EDRN industrial partners for the early detection of colorectal neoplasia. In this context we propose to (a) to clinically validate (via a methods comparison study) the performance of a point-of-care blood- based biomarker panel with the testing of serum/plasma samples obtained in clinics serving low-income and underserved communities and (b) to clinically validate an established 4-plex stool protein panel for early diagnosis of CRC. (3) To follow prospectively subjects enrolled in an established prospective Phase 2 validation trial to identify pre-diagnostic specimens which may be used to develop predictive markers.