Multi-omics analysis in IgM monoclonal gammopathies reveals epigenetic influence on oncogenesis via DNA methylation

Currently, the role of DNA methylation in the IgM-monoclonal gammopathy disease spectrum remains poorly understood. In the present study, a multi-omics prospective analysis was conducted integrating DNA methylation, RNA-seq and WES data in 34 subjects [23 WM, 6 IgM-MGUS, 5 normal controls]. Analysis was focused on defining differences between IgM-gammopathies (WM/IgM-MGUS) compared to controls, and specifically between WM and IgM-MGUS. Between groups, genome-wide DNA methylation analysis demonstrated a significant number of differentially methylated regions which were annotated according to genomic region. Next, integration of RNA-seq data was performed to identify potentially epigenetically deregulated pathways. We found that pathways involved in cell cycle, metabolism, cytokine/immune signaling, cytoskeleton, tumor microenvironment, and intracellular signaling were differentially activated and potentially epigenetically regulated. Importantly, there was a positive enrichment of CXCR4 signaling pathway along with several interleukin (IL-6, IL-8, IL15) signaling pathways in WM compared to IgM-MGUS. Further assessment of known tumor suppressor genes and oncogenes uncovered differential promoter methylation of several targets with concordant change in gene expression, including CCND1 and CD79B. Overall, this report defines how aberrant DNA methylation in IgM-gammopathies may play a critical role in the epigenetic control of oncogenesis and key cellular functions.