Circulating tumor DNA assisting lymphoma genetic feature profiling and identification

Lymphoma tissue biopsies cannot fully capture genetic features due to accessibility and heterogeneity. We aimed to assess the applicability of circulating tumor DNA (ctDNA) for genomic profiling and disease surveillance in classic Hodgkin lymphoma (cHL), primary mediastinal large B-cell lymphoma (PMBCL), and diffuse large B-cell lymphoma (DLBCL).

Tumor tissue and/or liquid biopsies of 49 cHLs, 32 PMBCLs, and 74 DLBCLs were subject to next-generation sequencing targeting 475 genes. The concordance of genetic aberrations in ctDNA and paired tissues was investigated, followed by elevating ctDNA-based mutational landscapes and the correlation between ctDNA dynamics and radiological response/progression.

ctDNA exhibited high concordance with tissue samples in cHL (78%), PMBCL (84%), and DLBCL (78%). In cHL, more unique mutations were detected in ctDNA than in tissue biopsies (P < 0.01), with higher variant allele frequencies (P < 0.01). Distinct genomic features in cHL, PMBCL, and DLBCL, including STAT6, SOCS1, BTG2, and PIM1 alterations, could be captured by ctDNA alone. Prevalent PD-L1/PD-L2 amplifications were associated with more concomitant alterations in PMBCL (P < 0.01). Moreover, ctDNA fluctuation could reflect treatment responses and indicate relapse before imaging diagnosis.

Lymphoma genomic profiling by ctDNA was concordant with that by tumor tissues. ctDNA might also be applied in lymphoma surveillance.