Machine learning model plasmaCHORD filters biological noise to improve liquid biopsy accuracy

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Researchers at Johns Hopkins Kimmel Cancer Center developed plasmaCHORD, a machine learning model that distinguishes tumor mutations from white blood cell mutations in liquid biopsy samples. The model improved accuracy from approximately 50% to 83% for clinically relevant mutations, helping clinicians select more effective targeted cancer treatments and avoid therapies unlikely to work.

Machine Learning Model Tackles Critical Challenge in Cancer Diagnostics

Researchers at the Johns Hopkins Kimmel Cancer Center have developed plasmaCHORD, a machine learning model designed to improve accuracy of liquid biopsy results by filtering out biological noise that has long complicated cancer treatment decisions

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. Published May 1 in Clinical Cancer Research, the study addresses a fundamental problem: when clinicians analyze cell-free DNA fragments from tumors in blood samples, they cannot easily distinguish tumor-derived mutations from mutations that accumulate in white blood cells through an aging-related process called clonal hematopoiesis

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"When you do a liquid biopsy, and you get the report back, and you see mutations, you do not know if the mutations are coming from the tumor or the white blood cells," explains co-first author Jenna Canzoniero, M.D., M.S., assistant professor of oncology at Johns Hopkins University School of Medicine

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. This uncertainty matters significantly because selecting mutation-targeted drugs requires targeting mutations in the cancer, not mutations from aging in white blood cells.

How PlasmaCHORD Distinguishes Tumor Mutations from White Blood Cell Mutations

Source: Newswise

Source: Newswise

The machine learning model uses distinct cfDNA fragmentation profiles to identify mutation origins. DNA fragments from tumors and white blood cells are "chopped up" in different ways, creating unique patterns that plasmaCHORD analyzes alongside factors like patient age, gene type, and specific mutation characteristics

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. Canzoniero and colleagues in the molecular oncology laboratory trained the model on liquid biopsy samples from 225 patients with breast, colorectal, esophageal, ovarian, or non-small cell lung cancer, verifying accuracy through matched genetic sequencing of patients' tumor cells and white blood cells.

Validation Demonstrates Substantial Performance Gains for Targeted Cancer Treatments

Testing plasmaCHORD on a separate cohort of 114 patients with breast, prostate, or non-small cell lung cancer from another institution using a different liquid biopsy sequencing platform confirmed the model's robust performance. The machine learning model improved the ability to correctly distinguish tumor from white blood cell mutations from approximately 50% to 83% for clinically relevant mutations

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. This improvement holds particular significance given that about one-third of mutations detected in tumor-naive liquid biopsies can originate from white blood cells, according to senior study author Valsamo Anagnostou, M.D., Ph.D., the Alex Grass Professor of Oncology and leader of the Johns Hopkins Molecular Tumor Board

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Clinical Applications Show Promise for Treatment Selection

The research team provided proof of concept demonstrating clinical utility by showing that plasmaCHORD's predictions helped clinicians avoid selecting likely ineffective targeted therapies for patients evaluated at the Johns Hopkins Molecular Tumor Board

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. "An artificial intelligence model applied to standard liquid biopsy tests could be both clinically valuable and quickly scalable," Anagnostou notes. The model's ability to work across different sequencing platforms suggests broad applicability for clinical applications.

Canzoniero indicates that plasmaCHORD can be used for both research and potentially clinical purposes to identify mutation origins when uncertainty exists. The team is already considering a future version with even better performance, signaling continued development in this area of precision oncology

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. The work was funded in part by the National Institutes of Health and published in Clinical Cancer Research.

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