GSE185157
Pre-neoplastic somatic mutations including MYD88L265P in lymphoplasmacytic lymphoma [scRNA-seq]
Normal-cell counterparts of solid and myeloid tumors accumulate mutations years before disease onset; whether this occurs in B-lymphocytes prior to lymphoma remains uncertain. We sequenced multiple stages of the B-lineage in elderly individuals and patients with lymphoplasmacytic lymphoma, a singular disease for studying lymphomagenesis because of high-prevalence of mutated MYD88. We observed similar accumulation of random mutations in B-lineages from both cohorts and, unexpectedly, found MYD88L265P in normal precursor and mature B-lymphocytes from lymphoma patients. We uncovered genetic and transcriptional pathways driving malignant transformation and leveraged these to model lymphoplasmacytic lymphoma in mice, based on mutated MYD88 in B-cell precursors and BCL2 overexpression. Thus, MYD88L265P is a pre-neoplastic event, which challenges current understanding of lymphomagenesis and may have implications for early detection of B-cell lymphomas. Overall design: single-cell RNA and BCR sequencing (scRNA/BCRseq) in a total of 40,169 B cells and PCs from three patients with IgM MGUS and two with LPL/WM