Masaaki Kume

A clinical analysis of 52 adult patients with hemophagocytic syndrome: the prognostic significance of the underlying diseases.

We retrospectively analyzed 52 adult patients with hemophagocytic syndrome (HPS). The underlying diseases were heterogeneous, including malignant lymphoma (lymphoma-associated hemophagocytic syndrome [LAHS]) in 26 patients, systemic lupus erythematosus in 3 patients, viral infections in 7 patients, and bacterial or fungal infections in 6 patients. More than 83% of patients received prednisolone as an initial treatment. Multiple-agent chemotherapies (cyclophosphamide, doxoru-bicin, and vincristine) were administered to 96% of LAHS patients after a histopathological diagnosis of lymphoma. HPSs were controllable and remissions were achieved except for those patients with LAHS, fulminant Epstein-Barr virus-ssociated HPS, and an immunosuppressive state. Twenty-one (81%) of the LAHS patients had uncontrollable HPS and died of multiple organ failure and disseminated intravascular coagulation.The median survival time of LAHS patients was 83 days. In contrast, 3 (12%) of the other HPS patients died of multiple organ failure within 44 days.The clinical manifestations and the laboratory findings of LAHS and the other HPSs were too variable to establish the prognosis based only on the findings at the onset of HPS. The prognostic factors of adult HPS were found to be the underlying diseases, notably malignant lymphoma and infections, accompanied by the immunosuppressive state.

The role of microRNA-150 as a tumor suppressor in malignant lymphoma

MicroRNA (miRNA; miR) is a class of small regulatory RNA molecules, the aberrant expression of which can lead to the development of cancer. We recently reported that overexpression of miR-21 and/or miR-155 leads to activation of the phosphoinositide 3-kinase (PI3K)–AKT pathway in malignant lymphomas expressing CD3−CD56+ natural killer (NK) cell antigen. Through expression analysis, we show in this study that in both NK/T-cell lymphoma lines and samples of primary lymphoma, levels of miR-150 expression are significantly lower than in normal NK cells. To examine its role in lymphomagenesis, we transduced miR-150 into NK/T-cell lymphoma cells, which increased the incidence of apoptosis and reduced cell proliferation. Moreover, the miR-150 transductants appeared senescent and showed lower telomerase activity, resulting in shortened telomeric DNA. We also found that miR-150 directly downregulated expression of DKC1 and AKT2, reduced levels of phosphorylated AKTser473/4 and increased levels of tumor suppressors such as Bim and p53. Collectively, these results suggest that miR-150 functions as a tumor suppressor, and that its aberrant downregulation induces continuous activation of the PI3K–AKT pathway, leading to telomerase activation and immortalization of cancer cells. These findings provide new insight into the pathogenesis of malignant lymphoma.

Somatic hypermutations in the VH segment of immunoglobulin genes of CD5-positive diffuse large B-cell lymphomas

De now CDS‐positive (CD5+) diffuse large B‐cell lymphoma (DLBL) has recently been identified as constituting a homogeneous subgroup with distinct clinicopathologic and genotypic characteristics, but its origin remains to he elucidated. Previous studies by sequence analysis of the variable region of the immunoglobulin heavy chain (VH) have shown that CDS5 B‐cell malignancies such as mantle cell lymphoma (MCL) and B‐cell chronic lymphocytic leukemia (B‐CLL) cells represent pre‐geminal center (pre‐GC) stage B cells in contrast with the post‐GC stage of most DLBLs, which show somatic hyper mutations in VH genes. In the present study, we investigated the VH sequence of de novo CD5+ DLBL to clarify whether CD5+ DLBL represents the pre‐GC stage, as do other CD5+ B‐cell malignancies, or the post‐GC stage, as is typical of DLBL. All eight cases (four CDS4 DLBL and four CDS‐negative (CD5−) DLBL) examined by us showed somatic hypermutatiohs in the VH segment and two of the CD5− DLBL cases showed intra‐clonal diversity, suggesting that CD5+ DLBLs were derived from the same maturation stage as CD5− DLBL, but were distinct from the other indolent CD5+ B‐cell lymphomas of B‐CLL and MCL. These data suggest that de novo CD5+ DLBLs do not merely lie within a continuous spectrum with B‐CLL and MCL, but represent a biologically distinct variant within the diagnostic framework of diffuse large B‐cell lymphoma.

Cytogenetic features of de novo CD5-positive diffuse large B-cell lymphoma: Chromosome aberrations affecting 8p21 and 11q13 constitute major subgroups with different overall survival

De novo CD5‐positive diffuse large B‐cell lymphoma (CD5+DLBCL) is regarded as a different clinicopathological entity from CD5‐negative DLBCL (CD5−DLBCL) and mantle cell lymphoma (MCL). Because only a few published cytogenetic studies of de novo CD5+DLBCL are available, we investigated chromosomal changes in 23 Japanese patients who had de novo CD5+DLBCL. A characteristic of cytogenetic abnormalities in de novo CD5+DLBCL was a high incidence of chromosomal aberrations affecting 8p21 and 11q13. Major chromosomal breakpoints were concentrated at 8p21, 11q13, and 3q27. Patients with 8p21 aberrations showed aggressive clinical features, including advanced stage of disease, elevated serum LDH level, poor performance status, and an inferior survival curve compared with patients who had 11q13 changes (P = .043). Chromosomal abnormalities of both 8p21 and 11q13 were not observed in the same patient, and each abnormality showed different chromosomal gains and losses. These results indicate that de novo CD5+DLBCL may occur in previously unidentified subgroups that differ in their chromosomal abnormalities. The conflicting results of previous studies on prognosis may thus be explained in part by the differences in chromosomal changes.

Bortezomib reduces the tumorigenicity of multiple myeloma via downregulation of upregulated targets in clonogenic side population cells.

Side population (SP) cells in cancers, including multiple myeloma, exhibit tumor-initiating characteristics. In the present study, we isolated SP cells from human myeloma cell lines and primary tumors to detect potential therapeutic targets specifically expressed in SP cells. We found that SP cells from myeloma cell lines (RPMI 8226, AMO1, KMS-12-BM, KMS-11) express CD138 and that non-SP cells include a CD138-negative population. Serial transplantation of SP and non-SP cells into NOD/Shi-scid IL-2γnul mice revealed that clonogenic myeloma SP cells are highly tumorigenic and possess a capacity for self-renewal. Gene expression analysis showed that SP cells from five MM cell lines (RPMI 8226, AMO1, KMS-12-BM, KMS-11, JJN3) express genes involved in the cell cycle and mitosis (e.g., CCNB1, CDC25C, CDC2, BIRC5, CENPE, SKA1, AURKB, KIFs, TOP2A, ASPM), polycomb (e.g., EZH2, EPC1) and ubiquitin-proteasome (e.g., UBE2D3, UBE3C, PSMA5) more strongly than do non-SP cells. Moreover, CCNB1, AURKB, EZH2 and PSMA5 were also upregulated in the SPs from eight primary myeloma samples. On that basis, we used an aurora kinase inhibitor (VX-680) and a proteasome inhibitor (bortezomib) with RPMI 8226 and AMO1 cells to determine whether these agents could be used to selectively target the myeloma SP. We found that both these drugs reduced the SP fraction, though bortezomib did so more effectively than VX-680 due to its ability to reduce levels of both phospho-histone H3 (p-hist. H3) and EZH2; VX-680 reduced only p-hist. H3. This is the first report to show that certain oncogenes are specifically expressed in the myeloma SP, and that bortezomib effectively downregulates expression of their products. Our approach may be useful for screening new agents with which to target a cell population possessing strong tumor initiating potential in multiple myeloma.

A New Variant Translocation of t(15;17) in a Patient with Acute Promyelocytic Leukemia (M3): t(15;19;17)(q22;p13;q12)

The reciprocal translocation (15;17) is specifically associated with acute promyelocytic leukemia [APL; M3 subtype according to French-American-British (FAB) classification]. A few patients with this disease have complex variant translocations. We describe a patient with M3 carrying t(15;19;17)(q22;p13;q12), which is a new type of variant translocation. The karyotypic interpretation was confirmed by Southern blot analysis with the use of RAR alpha and by fluorescence in situ hybridization (FISH) with the use of painting probes of chromosomes 15, 17, and 19 and a (15;17) translocation DNA probe. The results support the idea that the key event in APL is the formation of fusion gene PML/RAR alpha on the der(15).

Monitoring the Expression Profiles of Doxorubicin-Resistant K562 Human Leukemia Cells by Serial Analysis of Gene Expression

We examined the expression profiles of doxorubicin-resistant K562 cells by serial analysis of gene expression (SAGE) to identify novel and/or partially characterized genes that might be related to drug resistance in human leukemia. SAGE complementary DNA (cDNA) libraries were constructed from K562 and doxorubicin-resistant K562 (K562/ADM) cells, and concatamer sequences were analyzed with SAGE 2000 software.We used 9792 tags in the identification of 1076 different transcripts, 296 of which were similarly expressed in K562 and K562/ADM cells.There were 343 genes more actively expressed in K562/ADM than in parental K562 cells and 437 genes expressed less often in K562/ADM cells. K562/ADM cells showed increased expression of well-known genes, including the genes for spectrin β, eukaryotic translation initiation factor 1A (EIF1A), RAD23 homolog B, laminin receptor 1, and polyA-, RAN-, and PAI-1 messenger RNA-binding proteins. K562/ ADM cells showed decreased expression of the genes for fatty acid desaturase 1 (FADS1), hemoglobin ε 1, N-myristoyltransferase 1, hemoglobin α 2, NADH dehydrogenase Fe-S protein 6, heat shock 90-kDa protein, and karyopherin β1. Quantitative reverse transcription-polymerase chain reaction analysis confirmed the increased expression of EIF1A and the decreased expression of FADS1 in K562/ADM cells. Prior to this investigation, such differences in the expression of these genes in doxorubicinresistant leukemia cells were unknown. Although we do not provide any evidence in the present report for the potential roles of these genes in drug resistance, SAGE may provide a perspective into our understanding of drug resistance in human leukemia that is different from that provided by cDNA microarray analysis.

A PML/RARA chimeric gene on chromosome 2 in a patient with acute promyelocytic leukemia (M3) associated with a new variant translocation: t(2;15;17)(q21;q22;q21).

We describe a patient with acute promyelocytic leukemia (APL) carrying a new complex variant translocation of t(2;15;17)(q21;q22;q21). The karyotypic interpretation was confirmed by fluorescence in situ hybridization (FISH) with the use of painting probes of chromosomes 2, 15, and 17 and a PML/RARA dual color DNA probe. FISH showed a PML/RARA fusion gene on the der(2) instead of the der(15). These results suggest that the critical event in the development of APL is the formation of a PML/RARA chimeric gene, regardless of its locus in the genome.

Translocation (8;12;21)(q22.1;q24.1;q22.1): A New Masked Type of t(8;21)(q22;q22) in a Patient with Acute Myeloid Leukemia

The translocation t(8;21)(q22;q22) is found in 40% of cases of acute myeloid leukemia (AML) designated as the subtype M2 in the French-American-British (FAB) classification. The 8;21 translocation is clinically of interest because patients with this subtype have a good prognosis. We describe a masked type of the translocation, t(8;12;21)(q22.1;q24.1;q22.1). The translocation was first interpreted as t(8;12)(q22;q24) based on cytogenetics, but was reevaluated as a result of Southern blot and fluorescence in situ hybridization (FISH) analyses.

Fluorescence In Situ Hybridization Monitoring of BCR-ABL-Positive Neutrophils in Chronic-Phase Chronic Myeloid Leukemia Patients during the Primary Stage of Imatinib Mesylate Therapy

We describe a method for monitoring chronic myeloid leukemia (CML) patients treated with imatinib that uses fluorescence in situ hybridization (FISH) to detect BCR- ABL in peripheral blood (PB) granulocytes. First, we compared this method, termed Neutrophil- FISH, with interphase FISH (i-FISH) analysis of bone marrow (BM), i-FISH analysis of PB mononuclear cells, and conventional cytogenetic analysis (CCA) of BM in 30 consecutive CML patients. We found the percentage of BCR- ABL-positive neutrophils as determined by Neutrophil-FISH to correlate best with the percentage of Philadelphia chromosome-positive metaphases in the BM determined by CCA (y = 0.8818x + 5.7249; r2 = 0.968). We then performed a serial Neutrophil-FISH study of 10 chronic-phase CML patients treated with imatinib and found that the technique could clearly separate imatinib responders from nonresponders within 12 weeks of drug administration. There was a significant difference in the percentages of BCR- ABL-positive neutrophils between responder (mean ± SD, 18.2% ± 11.8%) and nonresponder (82.4% ± 5.1%) groups at 12 weeks (P <.0001, Student t test). Together with real-time quantitative polymerase chain reaction analysis, Neutrophil-FISH represents another useful method for monitoring CML patients during the primary myelosuppressive stage of imatinib therapy because it is a quick, simple, and reliable method for assessing cytogenetic response.