Hwi-Joong Yoon

Identification of six novel MYH9 mutations and genotype-phenotype relationships in autosomal dominant macrothrombocytopenia with leukocyte inclusions

AbstractThe autosomal dominant macrothrombocytopenia with leukocyte inclusions, May-Hegglin anomaly (MHA), Sebastian syndrome (SBS), and Fechtner syndrome (FTNS), are rare platelet disorders characterized by a triad of giant platelets, thrombocytopenia, and characteristic Döhle body-like leukocyte inclusions. The locus for these disorders was previously mapped on chromosome 22q12.3–q13.2 and the disease gene was recently identified as MYH9, the gene encoding the nonmuscle myosin heavy chain-A. To elucidate the spectrum of MYH9 mutations responsible for the disorders and to investigate genotype–phenotype correlation, we examined MYH9 mutations in an additional 11 families and 3 sporadic patients with the disorders from Japan, Korea, and China. All 14 patients had heterozygous MYH9 mutations, including three known mutations and six novel mutations (three missense and three deletion mutations). Two cases had Alport manifestations including deafness, nephritis, and cataracts and had R1165C and E1841K mutations, respectively. However, taken together with three previous reports, including ours, the data do not show clear phenotype–genotype relationships. Thus, MHA, SBS, and FTNS appear to represent a class of allelic disorders with variable phenotypic diversity.

FISH-negative cryptic PML–RARA rearrangement detected by long-distance polymerase chain reaction and sequencing analyses: a case study and review of the literature

Although a normal karyotype according to conventional cytogenetic analysis in association with cryptic t(15;17) has been infrequently reported in cases of acute promyelocytic leukemia (APL), a fluorescence in situ hybridization (FISH)-negative cryptic PML-RARA rearrangement is even more rare, with only 12 such APL cases of FISH-negative cryptic PML-RARA rearrangements in the literature. Reported here is an additional clinical APL case with a FISH-negative cryptic PML-RARA rearrangement, confirmed by long-distance DNA polymerase chain reaction method. Discussion includes a relevant literature review of similar cases. DNA-PCR can be a useful tool for the analysis of complex and cryptic rearrangements.

Clinical usefulness of free light chain concentration as a tumor marker in multiple myeloma.

Monoclonal immunoglobulin, as a marker for monoclonal gammopathy, is evaluated by protein electrophoresis (PEP) and immunofixation electrophoresis (IFE). However, PEP and IFE are not satisfactory in sensitivity, objectivity, and facility. Recently, a highly sensitive, automated immunoassay for measurement of free light chain (FLC) concentrations in serum and urine has been developed for the identification and monitoring of patients with monoclonal gammopathy. To explore the clinical usefulness of measurement of FLC concentrations, we measured the κ and λ FLC concentrations and calculated the κ/λ FLC ratios for three groups [multiple myeloma (MM), other diseases, and control] and compared the results of the FLC assay with the results of PEP or IFE. The concentrations of serum κ and λ FLCs and the κ/λ FLC ratios for the MM group and non-MM groups were distinct. In the MM group, some sera and urine samples had no evidence of M protein on PEP and IFE, but FLC assay showed abnormal concentrations of FLCs and abnormal κ/λ FLC ratios in most cases. As compared with the PEP, the κ/λ FLC ratio revealed higher sensitivity in all diagnostic ranges with different cutoff values. Particularly, when the cutoff value 2.0 for κ/λ FLC ratio was used, specificity and positive predictive value were largely improved than when the cutoff values 1.2 and 1.5 were used. These findings indicated that FLC assay enables to detect myeloma patients with very low M protein due to early stage or after therapy and to distinguish patients with monoclonal increase of FLC from patients with polyclonal increase of FLC due to other conditions, particularly using κ/λ FLC ratio 0.3–2.0 as a diagnostic range. Despite some technical limitations of the assay, the incorporation of κ/λ FLC ratios with FLC concentrations is useful in the detection of M protein, particularly with negative serum or urine IFE results, and differentiation of monoclonal gammopathies from patients with polyclonal increase in FLC due to other conditions.

Outcome of Adult Severe or Very Severe Aplastic Anemia Treated with Immunosuppressive Therapy Compared with Bone Marrow Transplantation : Multicenter Trial

To compare survival rates and long-term complications after bone marrow transplantation (BMT) or treatment with immunosuppressive agents (ISA) in the management of adult aplastic anemia (AA) and to identify prognostic factors associated with improved survival, we evaluated 229 adult AA patients treated with ISA from 1990 to 2001 and compared the results with those for 64 BMT recipients. Of 156 patients with severe aplastic anemia (SAA) or very severe AA treated with ISA (antithymocyte globulin [ATG]or ATG plus cyclosporine), 46.8% showed complete or partial response and 7.1% had relapses. After long-term follow-up, 1 case each of acute leukemia, myelodysplastic syndrome, and paroxysmal nocturnal hemoglobinuria developed.The 6-year survival rate was 69%. Response to ISA, disease severity, and low absolute neutrophil count (ANC) (≤200/mm3) were associated with poor survival. Patient age, sex, initial platelet count, etiology, or treatment regimen did not significantly affect survival. Cox regression analysis showed low ANC to be the only pretreatment variable significantly associated with poor survival (P = .000). Of 64 BMT recipients, 82.8% had sustained engraftment, and 12.5% experienced graft failure. Twenty (31.3%) of the patients developed grade II to IV acute graft-versus-host disease (GVHD), and 12 (18.8%) of the patients developed chronic GVHD.The 6-year survival rate was 79%. Patient age and sex, disease severity, etiology,ANC, initial platelet count, and treatment regimen did not affect survival. Survival of 83 AA patients, aged 14 to 40 years, treated with ISA was not statistically significant from that of 61 adult AA patients who underwent BMT (6-year survival rate, 65% and 79%, respectively). However, BMT in adult AA achieved long-term engraftment and a lower relapse rate than ISA.These results suggest that ISA can achieve a high response rate and long-term survival among patients with adult AA,regardless of disease severity. Further studies with larger numbers of patients and long-term follow-up are needed.

Signal transducer and activator of transcription 3 pathway mediates genipin‐induced apoptosis in U266 multiple myeloma cells

It has drawn a lot of attention to target signal transducer and activator of transcription 3 (STAT3) as a potential strategy for cancer therapeutics. Using several myelogenous cell lines, the effect of genipin (an active compound of Gardenia fruit) on the STAT3 pathway and apoptosis was investigated. Genipin suppressed the constitutive STAT3 activation in U266 and U937 cells and stimulated Src homology 2 domain‐containing phosphatase 1 (SHP‐1), which dephosphorylates and inactivates STAT3. Specifically, genipin blocked STAT3 activation via repressing the activation of c‐Src, but not Janus kinase 1 (JAK1). Genipin also downregulated the expression of STAT3 target genes including Bcl‐2, Bcl‐xL, Survivin, Cyclin D1, and VEGF. Conversely, protein tyrosine phosphatase inhibitor pervanadate blocked genipin induced STAT3 inactivation. Using DNA fragmentation or TUNEL assays, we demonstrated the apoptotic effect of genipin on U266, MM.1S, and U937 cells. Furthermore, genipin effectively potentiated the cytotoxic effect of chemotherapeutic agents, such as bortezomib, thalidomide, and paclitaxel in U266 cells. Our data suggest that through regulation of Src and SHP‐1, genipin antagonizes STAT3 for the induction of apoptosis in myeloma cells. J. Cell. Biochem. 112: 1552–1562, 2011.

Detection of t(3;5) and NPM1/MLF1 rearrangement in an elderly patient with acute myeloid leukemia: clinical and laboratory study with review of the literature.

We present a novel case of acute myeloid leukemia with an NPM1/MLF1 rearrangement in a 78-year-old Korean woman. The bone marrow chromosome study showed a complex karyotype: 46,XX,t(2;13) (q13;q32),der(3)t(3;5)(q25.1;q34),der(5)del(5)(?q31q34)t(3;5),inv(9)(p11q13)c,del(20)(q11.2)[13]/49,idem,+5,+8,+der(13)t(2;13)[7]. Multiplex gene rearrangement testing, cloning, and sequencing analyses revealed an NPM1/MLF1 fusion rearrangement between exon 6 of NPM1 (ENSG00000181163) and exon 2 of MLF1 (ENSG00000178053). Although t(3;5)(q25.1;q34) or the NPM1/MLF1 rearrangement has been reported mostly as a sole karyotypic abnormality in younger patients, it should also be considered in elderly patients with complex chromosomal abnormalities in acute myeloid leukemia or myelodysplastic syndrome.

High-dose therapy and autologous stem cell transplantation in Korean patients with aggressive T/NK-cell lymphoma

The proportion of aggressive T/NK-cell lymphoma in Korea is larger than in the West, and it shows a lower response to conventional chemotherapy and poorer survival than diffuse large B-cell lymphoma. This study was undertaken to evaluate the response rate and survival and to document the prognostic factors in patients with T/NK-cell lymphoma who have undergone high-dose therapy (HDT). Eligibility for the study was a mature T/NK-cell lymphoma with initially poor risk (as high or high intermediate risk on age-adjusted International Prognostic Index) or relapsed cases. Twenty-eight patients from 6 centers were reviewed retrospectively. The M : F ratio was 20 : 8, and median age was 36 years (range 16 – 60 years). Twelve patients had unspecified peripheral T-cell lymphomas, 7 anaplastic large-cell lymphomas, 6 nasal T/NK-cell lymphomas, and 3 angioimmunoblastic T-cell lymphomas. Disease status at transplant were initially poor risk in 15, chemosensitive relapse in 8 and chemoresistant relapse in 5 patients, respectively. A complete reponse (CR) after HDT comprised 20 patients, including 16 with continued CR. Absolute neutrophil count ( > 500/μl) recovered at a median 11 days after autologous stem cell transplantation in 26 patients. Two therapy-related mortalites occurred. Estimated 3-year event-free survival and overall survival (OS) ( ± SE) were 24 ± 9 and 42 ± 10 months, respectively. Only CR status after HDT influenced OS (P = 0.000). Therefore, an initial approach with effective induction and HDT may result in a better outcome in T/NK-cell lymphoma.

Genomic breakpoints and clinical features of MLL-TET1 rearrangement in acute leukemias

Recent rapid developments in new technology such as whole genome/exome sequencing have revealed that novel mutations in genes such as DNMT3A , IDH1 , IDH2 and TET2 contribute to the main process of leukemogenesis in patients with normal karyotype acute myeloid leukemia (AML).[1][1] Among these genes

Korean patients with superwarfarin intoxication and their outcome.

This observational study aimed at evaluating recent superwarfarin intoxication of Korean patients. Ten patients were diagnosed as or highly suspicious for superwarfarin intoxication. Case report forms described by attending hematologists of the patients were collected and analyzed. Bleeding symptoms were varied among the patients. Patients uniformly showed prolonged prothrombin time (PT) and activated thromboplastin time (aPTT) with decreased activity of vitamin K dependent coagulation factors. Positive serum brodifacoum test results in 4 of 5 requested patients contributed to confirmatory diagnosis. Psychiatric interview revealed an attempted ingestion in one patient. High dose vitamin K1 therapy promptly corrected prolonged PT and aPTT, but hasty discontinuation caused repeated bleeding diathesis in 6 patients. Route of intoxication was unknown or not definite among 8 of 10 patients. Three patients had a possibility of environmental exposure considering their occupations: there might be intoxication by transdermal absorption or inhalation. Therefore, high dose and prolonged use of vitamin K1 therapy is necessary for effective detoxification. Further detailed investigation on environmental exposure and efforts to improve availability of the blood level test in clinic are requested.

Matched-pair analysis to compare the outcomes of a second salvage auto-SCT to systemic chemotherapy alone in patients with multiple myeloma who relapsed after front-line auto-SCT.

The aims of this study were to investigate the outcomes of second salvage auto-SCT and to identify the impacts of a second auto-SCT compared with systemic chemotherapy alone on disease outcome. Data from 48 patients who underwent second auto-SCT were matched to 144 patients (1:3) who received systemic chemotherapy alone from the Korean Myeloma Registry. Groups were matched for nine potential prognostic factors and compared for treatment outcomes. The median age of matching-pairs at relapse was 55.5 years. A total of 156 patients (81%) received vincristine, doxorubicin and dexamethasone induction therapy before the first auto-SCT. Thirty-five patients (73%) in the second auto-SCT group received novel agent-based therapies before the second auto-SCT, and similar proportion in both groups received novel therapies after relapse of front-line auto-SCT. With a median follow-up of 55.3 months, patients who underwent a second auto-SCT had significantly better median OS (55.5 vs 25.4 months, P=0.035). In multivariate analysis for OS, <18 months time to progression after first auto-SCT, International Staging System III and salvage chemotherapy alone were independent predictors for worse OS. The outcomes of second auto-SCT appear to be superior to those of systemic chemotherapy alone. A randomized trial comparing both treatment strategies is required.