Whole-genome sequencing of Reed-Sternberg cells identifies outcome determinants in Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is a B-cell-derived malignancy characterized by rare Hodgkin and Reed–Sternberg (HRS) cells within an extensive inflammatory microenvironment. Although most patients achieve durable remission with first-line therapy, a subset relapse or experience disease progression. We performed whole-genome sequencing (WGS) of purified HRS-cell pools isolated from diagnostic biopsies of 76 cHL patients using DEPArray™ technology. Somatic copy number variations (CNVs), structural variants (SVs), and COSMIC mutational signatures were correlated with clinical characteristics, treatment response, and progression-free survival (PFS). HRS genomes displayed marked chromosomal instability with recurrent CNVs. Several CNV peaks were associated with baseline features and treatment response, while 2p11.2 amplification and 11q25 and 2p13.2 deletions were linked to inferior PFS. Mutational spectra were dominated by SBS5, SBS8, SBS84, SBS9 and SBS1, with an inverse SBS5–SBS9 axis and an AID-like SBS9-high/SBS5-low profile enriched in nodular sclerosis cHL. SV patterns were largely represented by SV2, with specific signatures associated with disease stage and treatment-related toxicity. TRACER-HL, integrating a Genomic Instability Score with relapse-associated CNVs, achieved an AUC of 0.81 and an NPV of 95%. These findings identify candidate genomic features associated with outcome and support further evaluation of genomically informed risk stratification strategies in cHL.