Enhancing mutation detection in multiple myeloma with an error-corrected ultra-sensitive NGS assay without plasma cell enrichment.

BACKGROUND: Risk stratification in multiple myeloma (MM) patients is crucial, and molecular genetic studies play a significant role in achieving this objective. Enrichment of plasma cells for next-generation sequencing (NGS) analysis has been employed to enhance detection sensitivity. However, these methods often come with limitations, such as high costs and low throughput. In this study, we explore the use of an error-corrected ultrasensitive NGS assay called positional indexing sequencing (PiSeq-MM). This assay can detect somatic mutations in MM patients without relying on plasma cell enrichment. METHOD: Diagnostic bone marrow aspirates (BMAs) and blood samples from 14 MM patients were used for exploratory and validation sets. RESULTS: PiSeq-MM successfully detected somatic mutations in all BMAs, outperforming conventional NGS using plasma cells. It also identified 38 low-frequency mutations that were missed by conventional NGS, enhancing detection sensitivity below the 5% analytical threshold. When tested in an actual clinical environment, plasma cell enrichment failed in most BMAs (14/16), but the PiSeq-MM enabled mutation detection in all BMAs. There was concordance between PiSeq-MM using BMAs and ctDNA analysis in paired blood samples. CONCLUSION: This research provides valuable insights into the genetic landscape of MM and highlights the advantages of error-corrected NGS for detecting low-frequency mutations. Although the current standard method for mutation analysis is plasma cell-enriched BMAs, total BMA or ctDNA testing with error correction is a viable alternative when plasma cell enrichment is not feasible.

Circulating Tumor DNA Reflects Histologic and Clinical Characteristics of Various Lymphoma Subtypes.

PURPOSE: We designed and evaluated the clinical performance of a plasma circulating tumor DNA (ctDNA) panel of 112 genes in various subtypes of lymphoma. MATERIALS AND METHODS: Targeted deep sequencing with an error-corrected algorithm was performed in ctDNA from plasma samples that were collected before treatment in 42 lymphoma patients. Blood buffy coat was utilized as a germline control. We evaluated the targeted gene panel using mutation detection concordance on the plasma samples with matched tissue samples analyzed the mutation profiles of the ctDNA. RESULTS: Next-generation sequencing analysis using matched tissue samples was available for 18 of the 42 patients. At least one mutation was detected in the majority of matched tissue biopsy samples (88.9%) and plasma samples (83.3%). A considerable number of mutations (40.4%) that were detected in the tissue samples were also found in the matched plasma samples. Majority of patients (21/42) were diffuse large B cell lymphoma patients. The overall detection rate of ctDNA in patients was 85.7% (36/42). The frequently mutated genes included PIM1, TET2, BCL2, KMT2D, KLHL6, HIST1H1E, and IRF8. A cutoff concentration (4,506 pg/mL) of ctDNA provided 88.9% sensitivity and 82.1% specificity to predict ctDNA mutation detection. The ctDNA concentration correlated with elevated lactate dehydrogenase level and the disease stage. CONCLUSION: Our design panel can detect many actionable gene mutations, including those at low frequency. Therefore, liquid biopsy can be applied clinically in the evaluation of lymphoma patients, especially in aggressive lymphoma patients.

DRP1 Inhibition Enhances Venetoclax-Induced Mitochondrial Apoptosis in TP53-Mutated Acute Myeloid Leukemia Cells through BAX/BAK Activation.

Although TP53 mutations in acute myeloid leukemia (AML) are associated with poor response to venetoclax, the underlying resistance mechanism remains unclear. Herein, we investigated the functional role of dynamin-related protein 1 (DRP1) in venetoclax sensitivity in AML cells with respect to TP53 mutation status. Effects of DRP1 inhibition on venetoclax-induced cell death were compared in TP53-mutated (THP-1 and Kasumi-1) and TP53 wild-type leukemia cell lines (MOLM-13 and MV4-11), as well as in primary AML cells obtained from patients. Venetoclax induced apoptosis in TP53 wild-type AML cells but had limited effects in TP53-mutated AML cells. DRP1 expression was downregulated in MOLM-13 cells after venetoclax treatment but was unaffected in THP-1 cells. Cotreatment of THP-1 cells with venetoclax and a TP53 activator NSC59984 downregulated DRP1 expression and increased apoptosis. Combination treatment with the DRP1 inhibitor Mdivi-1 and venetoclax significantly increased mitochondria-mediated apoptosis in TP53-mutated AML cells. The combination of Mdivi-1 and venetoclax resulted in noticeable downregulation of MCL-1 and BCL-xL, accompanied by the upregulation of NOXA, PUMA, BAK, and BAX. These findings suggest that DRP1 is functionally associated with venetoclax sensitivity in TP53-mutated AML cells. Targeting DRP1 may represent an effective therapeutic strategy for overcoming venetoclax resistance in TP53-mutated AML.

Clinical characteristics and prognostic factors of acquired haemophilia A in Korea.

INTRODUCTION: Acquired haemophilia A (AHA) treatment involves the haemostatic treatment for acute haemorrhage and immunosuppressive therapy (IST) to eradicate FVIII inhibitory antibodies. AIM: We assessed the clinical features of AHA and analysed treatment outcomes in Korea. We further identified prognostic factors affecting treatment outcomes. METHODS: Medical records of 55 patients with AHA from 18 institutions were reviewed retrospectively. Logistic and Cox regression analyses were performed to elucidate clinical factors affecting the achievement of complete remission (CR). The primary endpoint was time to CR after IST, and secondary endpoints were time to haemostasis, the achievement of CR, and overall survival (OS). RESULTS: Among the 55 patients, 50 (91%) had bleeding symptoms. Bleeding was severe in 74% of patients. Thirty-six (72%) patients received haemostatic therapy. Of the 42 patients who received IST, 23 (52%) received steroid alone, with a 52% response rate, and 10 (25%) received a combination of steroid and cyclophosphamide, with an 83% response rate. Five (16%) patients relapsed after a median duration of 220 days. There were eight deaths. In the Cox regression analysis, the FVIII inhibitor titre ≥ 20 BU/mL was the only significant prognostic factor affecting time to CR and haemostasis. No significant difference was observed in OS based on the inhibitor titre. CONCLUSION: The present study demonstrated the demographic data of AHA in Korea and showed that FVIII inhibitory antibody titre was a predictor of time to achieve CR after IST.

ULK1 inhibition as a targeted therapeutic strategy for FLT3-ITD-mutated acute myeloid leukemia.

BACKGROUND: In acute myeloid leukemia (AML), internal tandem duplication mutations in the FLT3 tyrosine kinase receptor (FLT3-ITD) are associated with a dismal outcome. Although uncoordinated 51-like kinase 1 (ULK1), which plays a central role in the autophagy pathway, has emerged as a novel therapeutic target for various cancers, its role in FLT3-ITD AML remains elusive. In this study, we evaluated the effects of ULK1 inhibition on leukemia cell death in FLT3-ITD AML. METHOD: We evaluated ULK1 expression and the levels of apoptosis and autophagy following ULK1 inhibition in FLT3-ITD AML cell lines and investigated the mechanism underlying apoptosis induced by ULK1 inhibition. Statistical analysis was performed using GraphPad Prism 4.0 (GraphPad Software Inc). RESULTS: FLT3-ITD AML cells showed significantly higher ULK1 expression than FLT3-wild-type (WT) AML cells. Two ULK1 inhibitors, MRT 68921 and SBI-0206965, induced apoptosis in FLT3-ITD AML cells, with relatively minimal effects on FLT3-WT AML cells and normal CD34-positive cells. Apoptosis induction by ULK1 inhibition was associated with caspase pathway activation. Interestingly, ULK1 inhibition paradoxically also induced autophagy, showing synergistic interaction with autophagy inhibitors. Hence, autophagy may act as a prosurvival mechanism in FLT3-ITD AML cells. FLT3-ITD protein degradation and inhibition of the ERK, AKT, and STAT5 pathways were also observed in FLT3-ITD AML cells following treatment with ULK1 inhibitors. CONCLUSION: ULK1 is a viable drug target and ULK1 inhibition may represent a promising therapeutic strategy against FLT3-ITD AML.

Early Cytomegalovirus Reactivation and Expansion of CD56brightCD16dim/-DNAM1+ Natural Killer Cells Are Associated with Antileukemia Effect after Haploidentical Stem Cell Transplantation in Acute Leukemia.

Cytomegalovirus (CMV) infection is a major complication after allogeneic hematopoietic stem cell transplantation but is suggested to exert a strong antileukemia effect in part due to alterations in the composition of natural killer (NK) cells. We evaluated the impact of early CMV reactivation and changes in NK cell subset recovery on relapse rate and survival after haploidentical stem cell transplantation (haploSCT) for acute leukemia. Fifty patients with acute leukemia who received haploSCT were analyzed. Expression of T cells and specific receptors (NKG2A, NKG2D, DNAM1, and CD57) on circulating NK cells (CD56brightCD16dim/- or CD56dimCD16+ cells) was serially measured using multiparametric flow cytometry. CMV reactivation during the first 100 days was observed in 41 patients (82%) at a median of 23 days after haploSCT. The incidence of acute graft-versus-host disease (GVHD) and chronic GVHD tended to be higher in patients with CMV reactivation, although this difference was not statistically significant. Multivariate analysis showed that CMV reactivation (P = .011) and a dose of infused T cells > 3.2 × 108/kg (P = .027) were independent predictors of a reduced relapse risk and only CMV reactivation (P = .029) was an independent predictor of improved leukemia-free survival. CD56brightCD16dim/-DNAM1+NK cell counts increased from day 30 to 90 in patients with CMV reactivation but decreased after day 30 in patients without CMV reactivation. An increase in CD56brightCD16dim/-DNAM1+ NK cells was not associated with the occurrence of chronic GVHD but was associated with a reduced cumulative relapse rate (16.4% versus 58.0%, P = .019). Multivariate analysis indicates that an increase in the CD56brightCD16dim/-DNAM1+NK cell count was an independent predictor of reduced relapse risk. Our study demonstrates a significant correlation between low relapse rates and CMV reactivation as well as the recovery of CD56brightCD16dim/-DNAM1+ NK cells, providing valuable information for understanding the plausible immunologic mechanism of the graft-versus-leukemia effect.

Causes of (18)F-FDG uptake on white adipose tissue.

White adipose tissue usually shows negligible fluorine-18-fluorodeoxyglucose ((18)F-FDG) uptake. In certain clinical conditions this (18)F-FDG uptake has been reported to be increased like in HIV patients under treatment, in exogenous Cushing's syndrome, in cases related to premedication and other cases.

High pre-transplant serum ferritin and busulfan-thiotepa conditioning regimen as risk factors for hepatic sinusoidal obstructive syndrome after autologous stem cell transplantation in patients with malignant lymphoma.

Few studies have evaluated the risk factors for hepatic sinusoidal obstructive syndrome (SOS) in patients with malignant lymphoma receiving autologous stem cell transplantation (ASCT). We retrospectively analyzed 132 malignant lymphoma patients who underwent ASCT. Intravenous busulfan-based conditioning regimens were used in 108 (81.8%) patients. The combination of heparin and ursodeoxycholic acid was used for prophylaxis of SOS. Hepatic SOS was developed in 10 (7.6%) patients at a median of 30 days post-ASCT. In nine (90.0%) patients, SOS was diagnosed after 20 days post-ASCT. Two patients developed severe SOS and eventually died from multiple organ failure. In multivariate analysis, the use of the busulfan-thiotepa conditioning regimen (p = 0.003) and a high pre-transplant serum ferritin level (≥ 950 ng/mL) (p = 0.003) were risk factors for hepatic SOS. The evaluation of pre-transplant serum ferritin may be helpful in determining the most appropriate conditioning regimen with a lower risk of SOS.

Early response to high-dose methotrexate, vincristine, and procarbazine chemotherapy-adapted strategy for primary CNS lymphoma: no consolidation therapy for patients achieving early complete response.

Optimal treatment strategies for primary central nervous system lymphoma (PCNSL) have not been established. In this study, we investigated the treatment outcomes and prognostic factors of high-dose methotrexate, vincristine, and procarbazine (MVP) chemotherapy followed by an interim response-adapted intensification strategy in immunocompetent patients with PCNSL. We evaluated the evidence of infection with Epstein-Barr virus (EBV) in both brain tumor tissue and whole blood. Forty patients were retrospectively reviewed. Ten (25 %) patients who achieved complete response (CR) in the interim analysis did not receive any additional consolidation treatment after completion of planned high-dose MVP chemotherapy. Additional radiotherapy (n = 9) or autologous stem cell transplantation (ASCT) (n = 7) was performed in patients who did not achieve CR in the interim analysis. The median age was 55 years. The overall CR rate was 62.5 % (n = 25), and the objective response rate was 75.0 %. Two-year overall survival (OS) was 59.8 %, and 2-year progression-free survival was 47.1 %. Grade 3 or 4 neutropenia and thrombocytopenia occurred in 47.5 and 32.5 % of patients, respectively. Treatment-related mortality was 15.0 % (n = 6), and four patients developed delayed neurotoxicity. There was no evidence of EBV-encoded RNA expression in brain tumor tissue. Ten (29.4 %) of 34 patients showed detectable EBV-DNA in whole blood. Poor performance status and EBV-DNA positivity in whole blood were significantly associated with inferior OS (p = 0.032, p = 0.023, respectively). We suggest that high-dose MVP chemotherapy followed by an early response-adapted intensification strategy may be effective and minimize the number of patients who receive radiotherapy or ASCT in the early course of treatment.

Aurora A kinase expression is increased in leukemia stem cells, and a selective Aurora A kinase inhibitor enhances Ara-C-induced apoptosis in acute myeloid leukemia stem cells.

BACKGROUND: The overexpression of Aurora A kinase (AurA) has been reported in various malignancies, including acute myeloid leukemia (AML). However, the expression of AurA and the effects of AurA inhibition in cancer stem cells are not yet fully understood. We investigated the expression and inhibition of AurA in AML stem cells (CD34(+)/CD38(-)). METHODS: Expression of AurA was investigated in cell lines (NB4 and KG1) that express high levels of CD34 and low levels of CD38. Primary AML cells were harvested from 8 patients. The expression of AurA and cell death induced by inhibition of AurA were analyzed in CD34(+)/CD38(-) cells. RESULTS: AurA was shown to be overexpressed in both primary AML cells and leukemia stem cells (LSCs) compared to normal hematopoietic stem cells. Inhibition of AurA plus cytarabine treatment in LSCs resulted in increased cytotoxicity compared to cytarabine treatment alone. Additional stimulation with granulocyte-colony stimulating factor (G-CSF) increased the cell death caused by AurA inhibition plus cytarabine treatment. CONCLUSION: To our knowledge, this is the first report describing increased expression of AurA in LSCs. Our results suggest that selective AurA inhibition may be used to reduce LSCs, and this reduction may be enhanced by stimulation with G-CSF. Further exploration of relationship between nuclear factor kappa-B and AurA inhibition and the potential of AurA inhibition for use in leukemia treatment is needed.

Risk factors for progression from cytomegalovirus viremia to cytomegalovirus disease after allogeneic hematopoietic stem cell transplantation.

Cytomegalovirus (CMV) disease is a major cause of infectious complications in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although patients undergoing allo-HSCT receive prophylactic and preemptive treatment for CMV, a subset of patients experience clinically significant CMV disease. This study investigated the risk factors for progression from CMV viremia to CMV disease during or after preemptive therapy in patients undergoing allo-HSCT. Between January 2006 and August 2010, 43 patients received preemptive therapy for CMV viremia after allo-HSCT. These patients experienced 74 episodes of CMV viremia. Nine of the patients (21%) and 12 of the episodes (16%) progressed to CMV disease. Univariate analysis identified several risk factors for progression to CMV disease, including high initial viral load (P = .020), leukopenia (P = .012), and neutropenia (P = .033) at the time of detection of CMV viremia. On multivariate analysis, leukopenia remained an independent predictor (hazard ratio, 4.347; P = .045). The rate of failure to clear CMV viremia after 1 cycle of preemptive therapy was higher in the leukopenia group than in the non-leukopenia group (60.0% versus 16.9%; P = .002). This indicates that leukopenia initially documented with CMV viremia is related to lower viral response to preemptive therapy and is a notable risk factor for progression from CMV viremia to CMV disease.

Clinical significance of B cell-activating factor (BAFF) and a proliferation-inducing ligand (APRIL) in acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation.

BACKGROUND: BAFF (B cell-activating factor) and APRIL (a proliferation-inducing ligand) are members of the tumor necrosis factor family and promote B cell survival and proliferation. We evaluated the correlation between serum concentration of BAFF or APRIL and severity of acute graft-versus-host disease (GVHD). METHODS: Fifteen patients who received allogeneic hematopoietic stem transplantation for leukemia and developed acute GVHD were enrolled. We determined serum concentrations of BAFF and APRIL at the onset of the first clinical manifestation of GVHD by enzyme-linked immunosorbent assay. RESULTS: Nine patients had grade 2 acute GVHD, and 6 had grade 3-4 acute GVHD. The BAFF serum concentration was higher in patients with grade 3-4 acute GVHD (1,093.42 in grade 2 vs. 2,171.99 pg/mL in grade 3-4), although the difference was not significant (P=0.077). However, the ratio of BAFF serum concentration to absolute lymphocyte count (ALC) (BAFF/ALC) was significantly higher in patients with grade 3-4 acute GVHD (P=0.045). The APRIL serum concentration and APRIL/ALC ratio showed similar results (P=0.077 and P=0.013, respectively). CONCLUSION: Patients with grade 3-4 acute GVHD had higher BAFF/ALC and APRIL/ALC ratios than patients with grade 2 acute GVHD. These findings suggest that B cells might play an important role in the development of acute GVHD, and that the BAFF and APRIL concentrations in serum might be significant predictive factors for estimating the severity of acute GVHD. Their clinical significance should be further evaluated in a larger patient population.