Aim: This study aimed to analyze two cases of marked hypo-high-density lipoprotein (HDL) cholesterolemia to identify mutations in ATP-binding cassette transporter A1 (ABCA1) and elucidate the ...molecular mechanism by which these novel pathological mutations contribute to hypo-HDL cholesterolemia in Tangier disease.Methods: Wild type and mutant expression plasmids containing a FLAG tag inserted at the C-terminus of the human ABCA1 gene were generated and transfected into HEK293T cells. ABCA1 protein expression and cholesterol efflux were evaluated via Western blotting and efflux assay. The difference in the rate of change in protein expression was evaluated when proteolytic and protein-producing systems were inhibited.Results: In case 1, a 20-year-old woman presented with a chief complaint of gait disturbance. Her HDL-C level was only 6.2 mg/dL. Tangier disease was suspected because of muscle weakness, decreased nerve conduction velocity, and splenomegaly. Whole-exome analysis showed compound heterozygosity for a W484* nonsense mutation and S1343I missense mutation, which confirmed Tangier disease. Cholesterol efflux decreased by a mixture of W484* and S1343I mutations. The S1343I mutation decreased the protein production rate but increased the degradation rate, decreasing the protein levels. This patient also had Krabbe disease. The endogenous ABCA1 protein level of macrophage cell decreased by knocking down its internal galactocerebrosidase.Case 2, a 51-year-old woman who underwent tonsillectomy presented with peripheral neuropathy, corneal opacity, and HDL-C of 3.4 mg/dL. Whole-exome analysis revealed compound heterozygosity for R579* and R1572* nonsense mutations, which confirmed Tangier disease.Conclusion: Case 1 is a new ABCA1 mutation with complex pathogenicity, namely, a W484*/S1343I compound heterozygote with marked hypo-HDL cholesterolemia. Analyses of the compound heterozygous mutations indicated that decreases in ABCA1 protein levels and cholesterol efflux activity caused by the novel S1343I mutation combined with loss of W484* protein activity could lead to marked hypo-HDL cholesterolemia. Galactocerebrosidase dysfunction could also be a potential confounding factor for ABCA1 protein function.
Immunoglobulin (Ig) heavy/light chain (HLC) assays enable the separate quantification of the different light chain types of each Ig class. We retrospectively analyzed the correlation of heavy/light ...chain ratio (HLCR) with clinical status and its impact on outcome in 120 patients with multiple myeloma (MM). Abnormal HLCR was seen more frequently in patients with poorer myeloma response, and it appeared to be more sensitive for detecting clonality in IgA myeloma compared to IgG myeloma after treatment. Among the 85 patients who achieved ≥VGPR, the patients remained HLCR abnormal were showed significantly shorter overall survival (OS) compared to those achieving a normal HLCR (not reached vs 55.5 months, P = 0.032). This correlation was seen in IgA myeloma patients (not reached vs 30.1 months, P = 0.014), but not in IgG myeloma patients when patients were analyzed separately. Univariate and multivariate analysis of factors that may affect survival identified abnormal HLCR at the best response as the only independent risk factor (hazard ratio, 4.7; 95% confidence interval, 1.4 – 15.26; P = 0.012) for shorter OS in this subset of patients. This study highlighted the HLC assay as a prognostic predictor in patients with IgA myeloma.
Immunoglobulin heavy/light chain (HLC) assay is a newer assay which can measure the different light chain types of each Ig class separately. To investigate the clinical utility of HLC assay, we measured HLC and FLC in relation to the IMWG responses in patients with IgG and IgA myeloma after treatment and evaluated its prognostic relevance.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Angioimmunoblastic T‐cell lymphoma (AITL) is a subtype of nodal peripheral T‐cell lymphoma (PTCL). Somatic RHOA mutations, most frequently found at the hotspot site c.50G > T, p.Gly17Val (G17V RHOA ...mutation) are a genetic hallmark of AITL. Detection of the G17V RHOA mutations assists prompt and appropriate diagnosis of AITL. However, an optimal detection method for the G17V RHOA mutation remains to be elucidated. We compared the sensitivity and concordance of next‐generation sequencing (NGS), droplet digital PCR (ddPCR) and peptide nucleic acid‐locked nucleic acid (PNA‐LNA) clamp method for detecting the G17V RHOA mutation. G17V RHOA mutations were identified in 27 of 67 (40.3%) PTCL samples using NGS. ddPCR and PNA‐LNA clamp method both detected G17V mutations in 4 samples in addition to those detected with NGS (31 of 67, 46.3%). Additionally, variant allele frequencies with ddPCR and those with NGS showed high concordance (P < .001). Three other RHOA mutations involving the p.Gly17 position (c.49G > T;50G > T, p.Gly17Leu in PTCL198; c.50G > T;51A > C, p.Gly17Val in PTCL216; and c.50G > A, p.Gly17Glu in PTCL223) were detected using NGS. These sequence changes could not appropriately be detected using the ddPCR assay and the PNA‐LNA clamp method although both indicated that the samples might have mutations. In total, 34 out of 67 PTCL samples (50.7%) had RHOA mutations at the p.Gly17 position. In conclusion, our results suggested that a combination of ddPCR/PNA‐LNA clamp methods and NGS are best method to assist the diagnosis of AITL by detecting RHOA mutations at the p.Gly17 position.
Angioimmunoblastic T‐cell lymphoma (AITL) is a distinct subtype of nodal peripheral T‐cell lymphoma (PTCL). Somatic RHOA mutations, (most frequently c.G50T, p.G17V RHOA mutation) are a genetic hallmark of AITL. Our results showed that a combination of NGS, ddPCR and PNA‐LNA clamp methods increased the detection rate of RHOA mutations at the p.G17 position.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The emergence of oligoclonal bands (OB) has been reported in patients with multiple myeloma (MM) after stem cell transplantation (SCT) or successful chemotherapy. However, their clinical relevance ...remains unclear. We reviewed the clinical records of MM patients from January 2006 to May 2014. Treatment response was evaluated by International Working Group (IMWG) criteria. Serum immunofixation tests were performed at least every 3 months if the patient achieved more than very good partial response (VGPR). Free light chain (FLC) and minimal residual disease measurement by multicolor flow cytometry (MFC) were performed to evaluate the response to treatment. Among the 163 patients included in the study, 40 developed OB. Detection rates of OB in patients with complete response (CR), VGPR and partial response (PR) or less were 51.8, 36.3 and 0%, respectively. Patients with OB showed better progression‐free survival (PFS) and overall survival (OS) rates than those without OB (P = 0.028 and P < 0.001, respectively). However, if the patients were limited to ≥VGPR or CR, development of OB did not affect PFS (P = 0.621 and P = 0.646, respectively) or OS (P = 0.189 and P = 0.766, respectively). OB was observed in 60% of patients after SCT, and in 36.6% of patients with more than VGPR without SCT (P < 0.001). Patients with OB tended to have less minimal residual disease than those without OB (P = 0.054) and its presence may affect the stringent CR criteria. In conclusion, the emergence of OB was seen exclusively in patients with favorable responses, but its emergence per se could not be translated to improved survival.
The emergence of oligoclonal bands (OB) in serum and/or urine immunofixation electrophoresis (IFE) has been reported with varying frequency in patients with stem cell transplantation or favourable response to chemotherapy in patients with myeloma, although its prognostic relevance remains unclear. We found that the emergence of OB was seen exclusively in patients with favourable responses, but its emergence per se was not associated with improved survival.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Primary central nervous system lymphoma (PCNSL) is a rare subtype of lymphoma that arises within the brain or the eyes. PCNSL recurs within the central nervous system (CNS) in most relapsed cases, ...whereas extra‐CNS relapse is experienced in rare cases. The present study aimed at identifying the presence of common precursor cells (CPC) for primary intra‐ and relapsed extra‐CNS tumors, and further assessing the initiating events in bone marrow (BM). Targeted deep sequencing was carried out for five paired primary intra‐ and relapsed extra‐CNS tumors of PCNSL. Two to five mutations were shared by each pair of intra‐ and extra‐CNS tumors. In particular, MYD88 mutations, L265P in three and P258L in one, were shared by four pairs. Unique somatic mutations were observed in all five intra‐CNS tumors and in four out of five extra‐CNS tumors. Remarkably, IgH clones in the intra‐ and the extra‐CNS tumors in two pairs were distinct from each other, whereas one pair of tumors shared identical monoclonal IgH rearrangement. In a cohort of 23 PCNSL patients, L265P MYD88 mutations were examined in tumor‐free BM mononuclear cells (MNC) in which the PCNSL tumors had L265P MYD88 mutations. L265P MYD88 mutations were detected by a droplet digital PCR method in nine out of 23 bone marrow mononuclear cells. These results suggest that intra‐ and extra‐tumors are derived from CPC with MYD88 mutations in most PCNSL, arising either before or after IgH rearrangement. The initiating MYD88 mutations may occur during B‐cell differentiation in BM.
It was suggested that primary intra‐central nervous system (CNS) tumors and relapsed extra‐CNS tumors are derived from common precursor cells with MYD88 mutations in most primary CNS lymphomas. The initiating MYD88 mutations may occur during B‐cell differentiation in BM.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Loss-of-function mutations in ten-eleven translocation-2 (TET2) are recurrent events in acute myeloid leukemia (AML) as well as in preleukemic hematopoietic stem cells (HSCs) of age-related clonal ...hematopoiesis. TET3 mutations are infrequent in AML, but the level of TET3 expression in HSCs has been found to decline with age. We examined the impact of gradual decrease of TET function in AML development by generating mice with Tet deficiency at various degrees. Tet2f/f and Tet3f/f mice were crossed with mice expressing Mx1-Cre to generate Tet2f/wtTet3f/fMx-Cre+ (T2ΔT3), Tet2f/fTet3f/wtMx-Cre+ (ΔT2T3), and Tet2f/fTet3f/fMx-Cre+ (ΔT2ΔT3) mice. All ΔT2ΔT3 mice died of aggressive AML at a median survival of 10.7 weeks. By comparison, T2ΔT3 and ΔT2T3 mice developed AML at longer latencies, with a median survival of ∼27 weeks. Remarkably, all 9 T2ΔT3 and 8 ΔT2T3 mice with AML showed inactivation of the remaining nontargeted Tet2 or Tet3 allele, respectively, owing to exonic loss in either gene or stop-gain mutations in Tet3. Recurrent mutations other than Tet3 were not noted in any mice by whole-exome sequencing. Spontaneous inactivation of residual Tet2 or Tet3 alleles is a recurrent genetic event during the development of AML with Tet insufficiency.
•Tet2 and Tet3 three-allele–deficient mice developed AML at longer latencies compared with four-allele–deficient mice.•Genetic abnormalities in the residual Tet2 or Tet3 wild-type allele were found in all the AMLs developed in the 3-allele deficient mice.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Summary In this study, we herein describe a 47-year-old Japanese woman who manifested inheritable non-alcoholic steatohepatitis (NASH) and severe dyslipidemia. Interestingly, her NASH progression was ...ameliorated by treatment with a sodium–glucose co-transporter 2 (SGLT2) inhibitor. This inheritability prompted us to comprehensively decode her genomic information using whole-exome sequencing. We found the well-established I148M mutation in PNPLA3 as well as mutations in LGALS3 and PEMT for her NASH. Mutations in GCKR may contribute to both NASH and dyslipidemia. We further mined gene mutations potentially responsible for her manifestations that led to the identification of a novel M188fs mutation in MUL1 that may be causally associated with her mitochondrial dysfunction. Our case may provide some clues to better understand this spectrum of disease as well as the rationale for selecting medications. Learning points While the PNPLA3 I148M mutation is well-established, accumulation of other mutations may accelerate susceptibility to non-alcoholic steatohepatitis (NASH). NASH and dyslipidemia may be intertwined biochemically and genetically through several key genes. SGLT2 inhibitors emerge as promising treatment for NASH albeit with interindividual variation in efficacy. Genetic background may explain the mechanisms behind the variation. A novel dysfunctional mutation in MUL1 may lead to metabolic inflexibilities through impaired mitochondrial dynamics and function.
Clonal Hematopoiesis and Solid Cancer Sakata-Yanagimoto, Mamiko; Makishima, Kenichi; Suehara, Yasuhito
Gan to kagaku ryoho
50, Issue:
2
Journal Article
Peer reviewed
In the hematopoietic system of healthy individuals, a phenomenon called clonal hematopoiesis, in which cells acquired somatic mutations are replaced with aging, has been discovered. The frequency of ...clonal hematopoiesis is higher in patients with solid tumors, than normal individuals. In addition, it is thought that infiltration of inflammatory cells with somatic mutations into cancer tissues may change the tumor microenvironment. Since clonal hematopoiesis is often found incidentally in gene panel testing of solid cancer tissues, it is of great significance to have an insight into clonal hematopoiesis in the medical care of solid cancer patients. In this paper, we describe the general concept of clonal hematopoiesis, the frequency of clonal hematopoiesis in patients with solid tumors, the characteristics of the clinical course in patients with clonal hematopoiesis, and microscopic observations of solid tumors in mouse models of clonal hematopoiesis.
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