Abstract 1315: Genomic signatures in red blood cell DNA enable early non-invasive detection of colorectal neoplasia: A multicenter clinical study.

Abstract Background: Colorectal cancer (CRC) causes substantial mortality, yet most cases arise from precursor lesions that are preventable if detected early. Existing non-invasive tests have limited sensitivity for advanced adenomas (AA), leaving a critical gap in early detection. Cytoplasmic DNA, including micronuclei and chromatin fragments, reflects genomic instability and systemic stress. Solid tumors can remotely induce DNA damage in hematopoietic progenitors, generating persistent DNA remnants in red blood cells (rbcDNA). We recently demonstrated that rbcDNA harbors tumor-associated genomic alterations that can detect early cancers with high accuracy. Here, we report the multicenter validation of an rbcDNA-based assay for early colorectal neoplasia detection. Methods: We enrolled 1,251 individuals who underwent colonoscopy with histopathologic confirmation and categorized them into three groups: CRC (n = 360), AA (n = 330), and non-advanced neoplasia controls (non-AN, n = 561). rbcDNA was extracted from 1-2 mL peripheral blood using our established workflow (Sun et al., PMID: 40341742), including red blood cell isolation, rbcDNA purification, library preparation, and low-coverage whole-genome sequencing (∼2×). Participants were randomly assigned in an 8:2 ratio into a discovery cohort and an internal test cohort, with comparable demographic characteristics. The discovery cohort was used to identify CRC- and AA-associated rbcDNA genomic features and to develop an integrated detection model, which was then evaluated in the internal test cohort to determine the optimal classification cutoff. The locked model was externally validated in two independent cohorts from the Second Hospital of Shandong University (n = 80) and Wenzhou Central Hospital (n = 110). Results: At a fixed 90% specificity cutoff determined in the internal test cohort, the classifier achieved sensitivities of 85% for AA and 95% for CRC. External validation in two independent cohorts from Shandong and Wenzhou confirmed consistent performance for colorectal neoplasia, with sensitivities of 78% and 80%, respectively. Notably, in the Wenzhou cohort, rbcDNA also detected AA and early-stage CRC cases that were negative by fecal occult blood testing. Conclusions: Our findings demonstrate that rbcDNA isolated from just 1-2 mL of peripheral blood enables accurate detection of AAs and early-stage CRC, supporting its potential utility for early diagnosis in clinical practice. A larger prospective clinical study (NCT05875584) will further validate the application of rbcDNA in early cancer detection. Citation Format: Xingyun Yao, Haobo Sun, Chengcheng Liu, Yurong Jiao, Xiangxing Kong, Jie Jin, Kefeng Ding, Jun Li, Xiaofei Gao. Genomic signatures in red blood cell DNA enable early non-invasive detection of colorectal neoplasia: A multicenter clinical study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1315.