Molecular features encoded in the ctDNA reveal heterogeneity and predict outcomein high-risk aggressive B-cell lymphoma

Inadequate molecular and clinical stratification of the patientswith high-risk diffuse large B-cell lymphoma (DLBCL) is a clinical challenge hampering the establishment of personalizedtherapeutic options. We studiedthe translational significance of liquid biopsy in a uniformly treated trial cohort.Pretreatment circulating tumor DNA (ctDNA)revealed hiddenclinical and biological heterogeneity, and high ctDNA burdendeterminedincreasedrisk of relapse and deathindependentlyof conventional risk factors. Genomic dissection of pretreatment ctDNA revealed translationally relevantphenotypic, molecular,and prognostic information that extended beyond diagnostic tissue biopsies.During therapy, chemorefractory lymphomas exhibited diverging ctDNA kinetics, whereas end-of-therapy negativity for minimal residual diseasecharacterized cured patientsand resolvedclinical enigmas, including false residual PET positivity.Furthermore, we discovered fragmentation disparities in the cell-free DNA that characterize lymphoma-derived ctDNA and,as a proof-of-conceptfor their clinical application,utilized machinelearningto show that end-of-therapy fragmentation patterns predict outcome. Altogether, wehave discovered novel molecular determinantsin the liquid biopsythatcan non-invasively guide treatment decisions.