Exai Bio, a next-gen liquid biopsy company, and researchers at UC San Francisco presented data from a new study in a poster entitled “Serum-based colorectal cancer detection using orphan noncoding RNAs” at the 2022 European Society of Medical Oncology (ESMO) meeting.

This case-control study of 191 subjects demonstrated that Exai’s novel, RNA-based platform accurately predicted colorectal cancer (CRC) cases versus non-cancer controls, both overall and across the full ranges of cancer stages and categories of tumor size/extent.  

Exai Bio’s technology is based on using cell-free RNA sequencing to identify a novel class of cancer-associated small non-coding RNAs, termed orphan non-coding RNAs (oncRNAs). Exai has created a proprietary library of >250,000 oncRNAs found in several types of cancer. Because oncRNAs can be actively secreted by cancer cells, they are readily detectable in the blood of cancer patients and are largely absent in healthy individuals, making them potentially robust biomarkers with high sensitivity and specificity. These features give the Exai Bio RNA-based platform—which uses artificial intelligence (AI) to identify cancer-specific patterns among thousands of oncRNAs—several scientific and practical advantages over tests that use circulating tumor-derived DNA in mutational, epigenomic, or fragmentomic analyses.

In the present poster, the Exai oncRNA-based model, which used machine learning, predicted CRC with a high overall sensitivity of 90.6% at 90% specificity. Predictions were also accurate for stage I cancer (92% sensitivity) and for the lowest categories of tumor size/extent, T1/T2 (92.3% sensitivity), indicating that even the earliest stage cancers and smallest tumors were detectable. Because of this, Exai Bio may be positioned to improve patient care through the development of a variety of liquid biopsy blood tests for CRC, including for early detection and monitoring of residual disease or recurrence.

“We are truly excited about these findings. Exai Bio is working to fulfill unmet needs that exist despite recent advances in liquid biopsy testing,” says Patrick Arensdorf, Exai Bio’s CEO. “This work demonstrates that Exai Bio can measure novel biomarkers in blood-derived samples to accurately predict colorectal cancer, including the earliest-stage and smallest tumors. By achieving greater than 90% sensitivity at 90% specificity, we exceeded the sensitivity hurdle in the published CMS National Coverage Determination for blood-based biomarker tests in CRC screening1. Moreover, the oncRNA-based liquid biopsy technology will be compatible with standard sample requirements enabling easy integration into conventional clinical workflows. These results build on our earlier study in breast cancer and validate the applicability of cell-free RNA methods in yet another tumor type.”


  1. NCD for Colorectal Cancer Screening Test (210.3). Medicare Coverage Decision database: Screening for Colorectal Cancer biomarker-based test: CAG-00454N decision memo 01/19/2021; cms.gov.