The significance of free light-chain ratio in light-chain monoclonal gammopathy of undetermined significance: a flow cytometry sub-study of the iStopMM screening study.

Light-chain (LC) monoclonal gammopathy of undetermined significance (MGUS) is a precursor of multiple myeloma (MM) and related conditions. LC-MGUS is characterized by free light-chain (FLC) levels outside defined reference intervals, indirectly indicating underlying plasma cell (PC) monoclonality. Next-generation flow cytometry (NGF) was used to evaluate clonal PC presence in bone marrow (BM) samples from individuals with LC-MGUS in the iStopMM study, aiming to assess the predictive value of the FLC ratio for clonal PC presence and its prognostic implications. BM samples from 61 individuals with LC monoclonal gammopathy were analyzed. Clonal plasma cells were detected in 53.6% of LC-MGUS samples (n = 28) and in all samples from individuals with more advanced conditions (n = 33). The FLC ratio was predictive of clonal PC presence for kappa-involved FLC ratios (p < 0.05; n = 42), with an optimal cutoff of 3.15 (96.7% sensitivity, 91.7% specificity). Of 195 individuals with kappa-involved LC-MGUS in follow-up within the iStopMM study, none with FLC ratios >1.65 to 3.15 progressed to MM (n = 124), whereas 4/71 (5.6%) with FLC ratios >3.15 progressed over median follow-up of 55 months. These findings support using a kappa-involved FLC ratio cutoff of >3.15 to more accurately identify individuals at increased risk of developing symptomatic PC disorders.

被引量：- 发表：1970

RSK1 dependency in FLT3-ITD acute myeloid leukemia.

Internal tandem duplications (ITD) in fms-like tyrosine kinase 3 (FLT3) represent the most common genetic alteration in de novo acute myeloid leukemia (AML). Here, we identify ribosomal protein s6 kinase a1 (RSK1) as a core dependency in FLT3-ITD AML and unveil the existence of crucial bi-directional regulation. RSK1 perturbation resulted in marked apoptosis and abrogated phosphorylation of FLT3 and associated downstream signaling cascades in FLT3-ITD AML cell lines. Using cycloheximide, MG-132, and ubiquitination assays, we further demonstrate mechanistically that RSK1 regulates FLT3-ITD activity, and protein stability through deubiqutinase USP1, which we identify as a second dependency. Importantly, multivariate analysis revealed heightened expression of RPS6KA1 and USP1 to be associated with poor patient prognosis, and these effectors may serve as biomarkers predictive of patient survival and therapeutic response to FLT3-ITD inhibitors. Lastly, RSK1 inhibition utilizing a first-in-class RSK inhibitor, PMD-026, that is currently undergoing Phase 2 development for breast cancer, diminished leukemic disease burden in MV4-11 xenograft and syngeneic Flt3ITDTet2KO leukemia models. These findings illustrate an unconventional and promising therapeutic strategy targeting FLT3-ITD leukemia.

被引量：- 发表：1970

Large B-cell lymphomas with CCND1 rearrangement have different immunoglobulin gene breakpoints and genomic profile than mantle cell lymphoma.

被引量：- 发表：1970

Current status and research directions in acute myeloid leukemia.

被引量：- 发表：1970

Colesevelam for lenalidomide associated diarrhea in patients with multiple myeloma.

被引量：- 发表：1970