Abstract
Ionizing radiotherapy (RT) is a widely used palliative and curative treatment strategy for malignancies. In solid tumors, RT-induced double strand breaks lead to the accumulation of indels, and their repair by non-homologous end-joining has been linked to the ID8 mutational signature in resistant cells. However, the extent of RT-induced DNA damage in hematologic malignancies and its impact on their evolution and interplay with commonly used chemotherapies has not yet been explored. Here, we interrogated 580 whole genome sequencing (WGS) from patients with large B-cell lymphoma, multiple myeloma, and myeloid neoplasms and identified ID8 only in relapsed disease. Yet, it was detected after exposure to both RT and mutagenic chemotherapy (i.e., platinum). Using WGS of single-cell colonies derived from treated lymphoma cells, we revealed a dose-response relationship between RT and platinum and ID8. Finally, using ID8 as a genomic barcode we demonstrate that a single RT-resistant cell may seed systemic relapse.Competing Interest StatementB.D. has received honoraria from Janssen and Sanofi for ad hoc advisory boards and independent data review committee for Janssen. O.L. has received research funding from: the National Institutes of Health (NIH), NCI, US Food and Drug Administration, MMRF, International Myeloma Foundation, Leukemia and Lymphoma Society, the Paula and Rodger Riney Myeloma Foundation, Perelman Family Foundation, Rising Tide Foundation, Amgen, Celgene, Janssen, Takeda, Glenmark, Seattle Genetics and Karyopharm; received honoraria and is on advisory boards for Adaptive, Amgen, Binding Site, BMS, Celgene, Cellectis, Glenmark, Janssen, Juno and Pfizer; and serves on independent data monitoring committees for clinical trials led by Takeda, Merck, Janssen and Theradex. 12 M.J. reports consultancy/advisory activities for Kite/Gilead and Novartis and has received research funding from Kite/Gilead, Incyte, and Lilly. F.M. has received honoraria from Medidata The remaining authors have no competing interests to report.