Homoharringtonine (omacetaxine mepesuccinate) as an adjunct for FLT3-ITD acute myeloid leukemia

An in vitro drug-screening platform on patient samples was developed and validated to design personalized treatment for relapsed/refractory acute myeloid leukemia (AML). Unbiased clustering and correlation showed that homoharringtonine (HHT), also known as omacetaxine mepesuccinate, exhibited preferential antileukemia effect against AML carrying internal tandem duplication of fms-like tyrosine kinase 3 (FLT3-ITD). It worked synergistically with FLT3 inhibitors to suppress leukemia growth in vitro and in xenograft mouse models. Mechanistically, the effect was mediated by protein synthesis inhibition and reduction of short-lived proteins, including total and phosphorylated forms of FLT3 and its downstream signaling proteins. A phase 2 clinical trial of sorafenib and HHT combination treatment in FLT3-ITD AML patients resulted in complete remission (true or with insufficient hematological recovery) in 20 of 24 patients (83.3%), reduction of ITD allelic burden, and median leukemia-free and overall survivals of 12 and 33 weeks. The regimen has successfully bridged five patients to allogeneic hematopoietic stem cell transplantation and was well tolerated in patients unfit for conventional chemotherapy, including elderly and heavily pretreated patients. This study validated the principle and clinical relevance of in vitro drug testing and identified an improved treatment for FLT3-ITD AML. The results provided the foundation for phase 2/3 clinical trials to ascertain the clinical efficacy of FLT3 inhibitors and HHT in combination.

Next-generation sequencing with a myeloid gene panel in core-binding factor AML showed KIT activation loop and TET2 mutations predictive of outcome

Clinical outcome and mutations of 96 core-binding factor acute myeloid leukemia (AML) patients 18–60 years old were examined. Complete remission (CR) after induction was 94.6%. There was no significant difference in CR, leukemia-free-survival (LFS) and overall survival (OS) between t(8;21) (N=67) and inv(16) patients (N=29). Univariate analysis showed hematopoietic stem cell transplantation at CR1 as the only clinical parameter associated with superior LFS. Next-generation sequencing based on a myeloid gene panel was performed in 72 patients. Mutations in genes involved in cell signaling were associated with inferior LFS and OS, whereas those in genes involved in DNA methylation were associated with inferior LFS. KIT activation loop (AL) mutations occurred in 25 patients, and were associated with inferior LFS (P=0.003) and OS (P=0.001). TET2 mutations occurred in 8 patients, and were associated with significantly shorter LFS (P=0.015) but not OS. Patients negative for KIT-AL and TET2 mutations (N=41) had significantly better LFS (P<0.001) and OS (P=0.012) than those positive for both or either mutation. Multivariate analysis showed that KIT-AL and TET2 mutations were associated with inferior LFS, whereas age ⩾40 years and marrow blast ⩾70% were associated with inferior OS. These observations provide new insights that may guide better treatment for this AML subtype.

Dysregulation of the intrinsic apoptotic pathway mediates megakaryocytic hyperplasia in myeloproliferative neoplasms

AIMS

Megakaryocyte expansion in myeloproliferative neoplasms (MPNs) is due to uncontrolled proliferation accompanied by dysregulation of proapoptotic and antiapoptotic mechanisms. Here we have investigated the intrinsic and extrinsic apoptotic pathways of megakaryocytes in human MPNs to further define the mechanisms involved.

METHODS

The megakaryocytic expression of proapoptotic caspase-8, caspase-9, Diablo, p53 and antiapoptotic survivin proteins was investigated in bone marrow specimens of the MPNs (n=145) and controls (n=15) using immunohistochemistry. The megakaryocyte percentage positivity was assessed by light microscopy and correlated with the MPN entity, JAK2V617F/CALR mutation status and platelet count.

RESULTS

The proportion of megakaryocytes in the MPNs expressing caspase-8, caspase-9, Diablo, survivin and p53 was significantly greater than controls. A greater proportion of myeloproliferative megakaryocytes expressed survivin relative to its reciprocal inhibitor, Diablo. Differences were seen between myelofibrosis, polycythaemia vera and essential thrombocythaemia for caspase-9 and p53. CALR-mutated cases had greater megakaryocyte p53 positivity compared to those with the JAK2V617F mutation. Proapoptotic caspase-9 expression showed a positive correlation with platelet count, which was most marked in myelofibrosis and CALR-mutated cases.

CONCLUSIONS

Disruptions targeting the intrinsic apoptotic cascade promote megakaryocyte hyperplasia and thrombocytosis in the MPNs. There is progressive dysfunction of apoptosis as evidenced by the marked reduction in proapoptotic caspase-9 and accumulation of p53 in myelofibrosis. The dysfunction of caspase-9, which is necessary for proplatelet formation, may be the mechanism for the excess thrombocytosis associated with CALR mutations. Survivin seems to be the key protein mediating the megakaryocyte survival signature in the MPNs and is a potential therapeutic target.

Curative Stem Cell Transplantation for Severe Hb H Disease Manifesting From Early Infancy: Phenotypic and Genotypic Analyses

Most people with Hb H disease live normal lives; however, a minority of cases requires lifelong regular transfusions. An atypical form of nondeletional Hb H disease was reported in a Thai boy, characterized by severe persistent hemolytic anemia since the age of 2 months. Molecular diagnosis revealed the apparent compound heterozygosity for the Southeast Asian (- -(SEA)) and α2 polyadenylation (polyA) signal (AATAAA>AATA- -) deletions. The proband was successfully treated with allogeneic hematopoietic stem cell transplantation (HSCT). Accurate phenotypic and genotypic diagnosis in atypically severe Hb H disease is helpful for the understanding of its pathophysiology, the institution of appropriate management, and provision of genetic counseling and prenatal diagnosis. Hematopoietic stem cell transplantation is a potentially curative treatment option for this severe α-thalassemia (α-thal) syndrome.

Genetic basis of persistent red blood cell microcytosis in the Chinese unexplained by phenotypical testing

AIMS

Hypochromic microcytic anaemia is the hallmark phenotype of thalassaemia. Current phenotypical tests do not provide a diagnosis in a small proportion of patients with red blood cell microcytosis. We aim to evaluate the genetic basis of red cell microcytosis in these cases in our Chinese population.

METHODS

We identified from a large cohort of 1684 unselected requests for thalassaemia testing 23 Chinese subjects who had unexplained microcytosis after phenotypical iron and haemoglobin studies. In 18 of these subjects with available DNA, extensive genotypical analysis of the α and β globin gene cluster was performed, including gap-PCR, multiplex amplification-refractory mutation system, Sanger sequencing and multiplex ligation-dependent probe amplification.

RESULTS

Occult single and double α globin gene (HBA1, HBA2) deletions and α thalassaemic haemoglobinopathies (Haemoglobin Quong Sze, Haemoglobin Constant Spring) were the genetic basis for the microcytosis. Occult β globin gene (HBB) mutations and δ globin gene (HBD) abnormalities masking β thalassaemia are not seen.

CONCLUSIONS

A cost-effective genotyping approach for the detection of these occult globin gene mutations can be proposed. The identification of these mutations is important for making a diagnosis and for the provision of accurate genetic counselling. (This paper adds to our understanding of the genetic basis of red blood cell microcytosis in clinical practice, and it provides a cost-effective approach for genotyping in diagnostic laboratories).

Diagnosis and prevention of thalassemia

Thalassemia is the most common monogenic inherited disease worldwide and it affects most countries to various extents. This review summarizes the current approaches to phenotypic and genotypic diagnosis of thalassemia in clinical practice. Prevention strategies that encompass carrier screening, genetic counseling and prenatal diagnosis are discussed. The importance of public education and an awareness of a changing perception regarding this group of diseases are emphasized. It also addresses the impact of the rapidly increasing knowledge in disease severity modification by hemoglobin F (Hb F).

Central diabetes insipidus: an unusual complication in a child with juvenile myelomonocytic leukemia and monosomy 7

Central diabetes insipidus (DI) is well-documented as a presenting feature of myelodysplastic syndrome and acute myeloid leukemia in adults. However, DI is unusual in pediatric patients with myeloid malignancies. We report here this rare complication in a child with neurofibromatosis type 1 who developed juvenile myelomonocytic leukemia and monosomy 7. Our case and previously reported cases of DI arising as a complication in myeloid malignancies demonstrate a close association with deletion of chromosome 7. The clinical characteristics and outcomes of these uncommon cases in children are reviewed and discussed.

Bacterial stimulation of the TLR-MyD88 pathway modulates the homeostatic expression of ileal Paneth cell α-defensins

Paneth cell α-defensins are antimicrobial peptides involved in the control of the intestinal microbiota and immunological homeostasis. In mice, they are encoded by multiple, highly homologous genes (Defa). The transcriptional activity of ileal Defa genes was studied in response to pharmacological and genetic perturbations of the intestinal environment of C57BL/6 mice. Defa gene transcription was sensitive to oral antibiotic administration suggesting that commensal microbes regulate Defa expression. Ileal microbiota analysis showed that decreased transcription of Defa genes correlated with depletion of Lactobacillus. Defa expression was partially restored in vivo by lactobacillus administration to antibiotic-treated mice. Defa transcripts were less abundant in ex vivo, microbiota-free intestinal explants but recovered after explant exposure to UV-killed bacteria, Toll-like receptor (TLR)-2 or TLR4 agonists. Genetic deficiency of several TLRs or MyD88 led to dramatic drops in Defa transcription in vivo. These results show that Paneth cell Defa genes are regulated by commensal bacteria through TLR-MyD88 signaling and provide a further understanding of the dysregulation of intestinal homeostasis that occurs as a result of imbalances in the populations of commensal bacteria.

First reported case of prenatal diagnosis for pyruvate kinase deficiency in a Chinese family

We describe the first case of prenatal diagnosis for pyruvate kinase (PK) deficiency in Chinese and emphasize that this disease is an important differential diagnosis in pediatric patients with non-spherocytic hemolytic anemia. A Han Chinese child with a history of severe transfusion-dependent hemolytic anemia was diagnosed to have PK deficiency. Prenatal diagnosis was performed on the second child based on the genetic findings from the family. The index patient was compound heterozygous for a missense mutation (c.1073G > A. p.Gly358Glu) from his father and a large deletion (c.283 + 1914_c.1434del5006) from his mother. The fetus was a simple heterozygote for the paternal mutation. Pregnancy was allowed to continue and a healthy baby was born. Severe PK deficiency warranting prenatal diagnosis is seen in Han Chinese. Genetic characterization and genotype-phenotype correlation studies on PKLR in different populations are indicated to better define the role of prenatal diagnosis in PK deficiency.

A single-center cytogenetic study of 629 Chinese patients with de novo acute myeloid leukemia--evidence of major ethnic differences and a high prevalence of acute promyelocytic leukemia in Chinese patients

Cytogenetic information is important in the diagnosis, classification, and prognostication of acute myeloid leukemia (AML). Data obtained from multicenter treatment trials are well published. In this study, we contribute cytogenetic data from a large series of 629 Chinese patients with de novo AML that were karyotyped in a single laboratory. A higher prevalence of acute promyelocytic leukemia was observed when compared with non-Chinese series. The difference was most prominent in the younger age group. Abnormalities at chromosomal region 11q23 and inv(16) seemed uncommon. These ethnic differences may indicate underlying genetic susceptibility to AML development and/or environmental differences. More comprehensive data on AML in the elder population are needed to assess the role of cytogenetics in predicting prognosis and guiding treatment in this large subgroup of patients.

Hb A2 Hong Kong - A novel δ-globin variant in a Chinese family masks the diagnosis of β-thalassemia trait

A 42-year-old Chinese woman (FP) was the mother of a patient with β-thalassemia major (β-TM) due to a compound heterozygosity for β(0)-thalassemia (β(0)-thal) mutations. She was also found to have a low Hb A(2) level of 1.6% by high performance liquid chromatography (HPLC) despite being a heterozygous carrier of the codons 41/42 (-TCTT) (HBB:c.126_129delCTTT) β(0)-thal mutation. Doubling the amount of hemolysate loaded for chromatography revealed a widened Hb A(2) peak and raised the level to 4.1%, consistent with β-thal trait. Direct nucleotide sequencing detected a novel δ-globin gene mutation at codon 29 (HBD:c.89G>A), which leads to a glycine to aspartic acid substitution. A homologous mutation at codon 29 in the β-globin gene [Hb Lufkin or β29(B11)Gly→Asp] has been reported in Black families. This report highlights the importance of genotype-phenotype correlation and the potential pitfall of relying on Hb A(2) level for phenotypic diagnosis of β(0)-thal trait.

Epigenetic silencing of MIR203 in multiple myeloma

Epigenetic inactivation of tumour suppressor microRNAs has been implicated in carcinogenesis. We studied the promoter methylation of MIR203 in eight normal marrow controls, eight multiple myeloma (MM) cell lines, 20 monoclonal gammopathy of undetermined significance (MGUS), 123 diagnostic MM and 19 relapsed MM samples by methylation-specific polymerase chain reaction. Promoter of MIR203 was unmethylated in normal controls but homozygously methylated in 25% MM cell lines. Treatment with 5-Aza-2'-deoxycytidine led to promoter demethylation and MIR203 re-expression. Cyclic AMP responsive element binding protein 1 (CREB1) mRNA was predicted as a MIR203 direct target. Luciferase activity was reduced in constructs carrying wild-type CREB1 3'UTR upon MIR203 expression but not in those carrying mutant CREB1 3'UTR. Moreover, restoration of MIR203 led to downregulation of CREB1 protein and inhibition of myeloma cell proliferation. In primary samples, MIR203 methylation occurred in 25·0% MGUS, 23·6% diagnostic MM, and 21·1% relapsed MM samples. In conclusion, MIR203 methylation is disease-specific with reversible gene silencing in MM. MIR203 is a tumour suppressor microRNA inhibiting cellular proliferation by targeting CREB1 mRNA in MM. Comparable occurrence of MIR203 methylation in MGUS and MM at diagnosis or relapse suggested that MIR203 methylation may be an early event in myelomagenesis instead of being acquired during disease progression.

Common association of haemolytic uraemic syndrome with invasive Streptococcus pneumoniae infection in five Chinese paediatric patients

Haemolytic uraemic syndrome is an important cause of acute renal impairment in childhood. We review the incidence, and clinical and laboratory features of haemolytic uraemic syndrome in a Chinese population. Five patients were identified from 2006 to 2008. All patients were young children with associated invasive Streptococcus pneumoniae pulmonary infection. Serotypes 3, 14, and 19A were confirmed in four patients. The classical post-diarrhoeal form associated with Escherichia coli (O157:H7) infection was not seen. One patient died of acute respiratory failure. Streptococcus pneumoniae infection, as an associated condition in haemolytic uraemic syndrome, is important and relatively common in Chinese patients, especially among children. The acute clinical picture is similar to that reported in the western literature, except for an uncommon association with meningitis. The medium-term renal outcome of the Chinese population appears to be more favourable than the Caucasians. Widespread vaccination against Streptococcus pneumoniae may have resulted in changes in bacterial epidemiology and clinicians should be continuously aware of this severe disease. The use of washed blood components for transfusion in the acute stage requires further study.

Haemoglobin Bonn in a Chinese family as a cause of spurious hypoxaemia measured by pulse oximetry

Haemoglobin (Hb) Bonn is a newly described benign Hb variant that causes falsely depressed oxygen saturation as measured by pulse oximetry. It was found to be associated with mild haemolysis. Since its first report in a German family, no further cases have been documented in the literature. We report the first Chinese family with this Hb variant and confirm its unusual clinical presentation. No evidence of haemolysis was seen. The absence of consistent abnormalities in routine Hb tests such as high-performance liquid chromatography and gel electrophoresis means that spurious hypoxaemia is the only clue to its presence, and genotypic analysis is the preferred method for definitive diagnosis. Its positive identification is important for counselling and will help to avoid unnecessary investigation and treatment for this benign condition.

A dual colour dual fusion fluorescence in situ hybridisation study on the genesis of complex variant translocations in chronic myelogenous leukaemia

Complex variant 9;22 translocations occur in a significant minority of chronic myelogenous leukaemia (CML) patients. Different mechanisms of their formation have been described. We report dual colour dual fusion fluorescence in situ hybridisation data in 12 Chinese CML patients with complex translocations. Three previously reported breakpoint hotspots in a third partner chromosome (14q32, 17q25, 1q21) were observed. In 10/12 (83.3%) patients, the abnormality occurred as a single step 3-break event. Only a single abnormal clone harbouring the complex translocation was seen in this group. The remaining 2 cases in the chronic phase showed a 4-break mechanism (2/12, 16.7%). Deletion of 5' ABL at der(9) was not observed in any of the 12 patients, however, the loss of 3' BCR was observed in 1 patient (1/12, 8.3%). Together with previous findings, these data suggest that these variant translocations occur more often as a 3-break single-step process with no reciprocal ABL-BCR fusion. On the other hand, a 4-break event is also regularly seen during the initial stages of leukaemogenesis, which likely predisposes to der(9) deletion. The observed difference in rates of der(9) deletion reported in a series of CML patients with variant translocations may be related to a difference in rates of a 4-break event.

Functional alterations of Lin-CD34+CD38+ cells in chronic myelomonocytic leukemia and on progression to acute leukemia

The functional behavior of hematopoietic stem cell (HSC) and progenitors in chronic myelomonocytic leukemia (CMML) and on disease progression is little known. We performed cell proliferation, apoptosis, hematopoietic colony forming/replating and differentiation potential studies in the purified subpopulations of Lin(-)CD34(+)CD38(-) and Lin(-)CD34(+)CD38(+) cells from 16 CMML with 6 cases after acute myeloid leukemia transformation (AML-t). We observed an expansion of the hematopoietic progenitor pool (Lin(-)CD34(+) cells) in AML-t comprising mainly Lin(-)CD34(+)CD38(+) cells. The Lin(-)CD34(+)CD38(+) cells in AML-t displayed high proliferative activity, resistance to apoptosis, enhanced myeloid colony formation/replating ability and a complete dendritic cell (DC) differentiation block. Our findings suggest Lin(-)CD34(+)CD38(+) cells instead of Lin(-)CD34(+)CD38(-) cells could be the target(s) of secondary genetic lesions underpinning progression from CMML to AML, which have implications for the further study of the biology of leukemic transformation and the design of new strategies for the effective treatment of CMML.

Diagnostic utility of dual fusion PML/RARalpha translocation DNA probe (D-FISH) in acute promyelocytic leukemia

Translocation(15;17) leading to the formation of fusion gene PML/RARalpha is the diagnostic hallmark of acute promyelocytic leukemia (APL). Interphase fluorescence in situ hybridization (FISH) is one of the diagnostic tools employed for the detection of PML/RARalpha rearrangement. Using a dual color dual fusion (D-FISH) PML/RARalpha translocation DNA probe which hybridises both to PML/RARalpha and RARalpha/PML fusion genes, we characterised the FISH pattern of 52 APL patients at diagnosis and correlated the findings with conventional cytogenetics and RT-PCR analysis. The diagnostic sensitivity of the probe for PML/RARalpha was 100%. Seven patients had atypical D-FISH patterns; two had a masked PML/RARalpha fusion signal caused by the insertion of PML into RARalpha on 17q; 3 had an extra copy of PML/RARalpha in the form of isochromosome der(17)(q10)t(15;17) and one had duplication of the normal RARalpha gene with an ider(17q) masquerading as i(17)(q10). There was also one case of t(7;17;15) with a typical D-FISH pattern and in which metaphase FISH suggested an unusual 4-point break. In summary, PML/RARalpha D-FISH is a highly sensitive method for confirming diagnosis of APL. However D-FISH cannot be solely relied on for the diagnosis of APL owing to atypical patterns which are infrequently observed in cases with additional 17q structural abnormalities, gene insertion and gene duplication.

A novel beta-delta globin gene fusion, anti-Lepore Hong Kong, leads to overexpression of delta globin chain and a mild thalassaemia intermedia phenotype when co-inherited with beta(0)-thalassaemia

Anti-Lepore haemoglobins (Hb) are rare betadelta fusion variants that arise from non-homologous crossover during meiosis, resulting in a delta-betadelta-beta configuration. A novel anti-Lepore mutation (anti-Lepore Hong Kong) was found in two Chinese families with raised Hb A(2). Direct sequencing revealed a crossover within a 54-bp region spanning the junction of cap site (CAP) and exon 1, which predicted the production of normal delta-globin. Determination of alpha/beta-mRNA ratios by quantitative real-time polymerase chain reaction demonstrated downregulation of the beta gene in cis due to the interposed betadelta fusion gene. Although heterozygotes have normal red cell indices and are clinically silent, compound heterozygotes with beta(0) mutation in trans produce a mild thalassaemia intermedia phenotype with a markedly raised Hb A(2) level that may mimic clinically mild Hb E-beta(+)-thalassaemia. Awareness of the presence of anti-Lepore Hong Kong will help to resolve diagnostic problems in regions with significant prevalence of globin disorders.

A laboratory strategy for genotyping haemoglobin H disease in the Chinese

BACKGROUND

The thalassaemias are the commonest blood disorders worldwide, with South East Asia and southern China as areas of high prevalence. Accurate diagnosis of these disorders helps in clinical management with improved outcome.

METHODS

The alpha-globin genotypes of 100 Chinese patients in Hong Kong with haemoglobin H (Hb H) disease were characterised. Single-tube multiplex gap-PCR was used to detect --(SEA), -alpha(3.7) and -alpha(4.2), while Hb CS, Hb QS and codon 30 (DeltaGAG) were identified by single-tube multiplex amplification refractory mutation system (ARMS). Automated direct nucleotide sequencing of the amplified alpha2- and alpha1-globin genes was performed to characterise other non-deletional alpha-thalassaemia determinants.

RESULTS

In the 100 cases studied, 99 cases had --(SEA) in combination with deletional alpha(+)-thalassaemia or non-deletional alpha-globin gene mutation involving the alpha2-globin gene. In 70 cases of the deletional form, 43 cases showed the genotype of (--(SEA)/-alpha(3.7)) and 27 cases of (--(SEA)/-alpha(4.2)). Three of the 27 cases of (--(SEA)/-alpha(4.2)) were found to have Hb Q-Thailand linked in-cis with -alpha(4.2). The remaining 30 cases were of non-deletional form with the following genotypes: 11 cases of (--(SEA)/alpha(HbCS)alpha), 9 cases of (--(SEA)/alpha(HbQS)alpha), 3 cases of (--(SEA)/alpha(cd30 (DeltaGAG))alpha), 3 cases of (--(SEA)/alpha(cd31)alpha), 2 cases of (--(SEA)/alpha(poly-A)alpha), 1 case of (--(SEA)/alpha(HbWestmead)alpha) and 1 case of (--(non-SEA)/alpha(HbQS)alpha).

CONCLUSIONS

Based on two rapid diagnostic tests, multiplex gap-PCR and multiplex ARMS, more than 90% of the cases were genetically characterised. This laboratory strategy should be widely applicable for genetic diagnosis of alpha-thalassaemia.

High BCL6 expression predicts better prognosis, independent of BCL6 translocation status, translocation partner, or BCL6-deregulating mutations, in gastric lymphoma

To investigate the role of BCL6 in the pathogenesis of gastric lymphoma, we analyzed the BCL6 promoter region for BCL6 translocations, somatic hypermutations, and deregulating mutations in 43 gastric lymphomas, including 4 extranodal marginal-zone B-cell lymphomas of mucosa-associated lymphoid tissues (MALT lymphomas), 33 diffuse large B-cell lymphomas (DLBCLs), and 6 composite DLBCLs with residual MALT lymphoma (DLCLMLs). BCL6 promoter substitutions by immunoglobulin (Ig) and non-Ig translocation partners, resulting in its deregulation, were frequently involved in DLBCL (36.4%) and DLCLML (50%). Two novel BCL6 translocation partner genes, 28S rRNA and DMRT1, and a new BCL6 translocation breakpoint in intron 2 were also identified. Deregulating mutations were found only in DLBCL (24.2%), which correlated significantly with high BCL6 protein expression. Significantly, high BCL6 expression correlated strongly with longer overall survival (OS), independent of mechanism in gastric DLBCL and DLCLML. Gastric DLBCLs were further subclassified into germinal center B-cell-like (GCB) and non-GCB subgroups immunohistochemically. High BCL6 expression was detected in all GCB cases, irrespective of BCL6 genetic alterations. In the non-GCB subgroup, BCL6-deregulating mutations correlated significantly with high BCL6 expression level. No significant correlation was found between the BCL6 expression level and OS in the non-GCB subgroup, which had significantly poorer prognosis than the GCB subgroup.

Diffuse large B-cell lymphoma with occult marrow involvement and a novel t(9;10)(q32;q22)

A 33-year-old man was found to have stage IV diffuse large cell lymphoma with visceral, cutaneous, and central nervous system involvement. Although examination of the posttreatment bone marrow failed to show morphologic evidence of lymphoma involvement, cytogenetic study of the marrow mononuclear cells showed the presence of a clonal abnormality t(9;10)(q32;q22), a hitherto undescribed chromosomal abnormality in diffuse large B-cell lymphoma.

Arsenic trioxide in comparison with chemotherapy and bone marrow transplantation for the treatment of relapsed acute promyelocytic leukaemia

BACKGROUND

The best overall treatment strategy for patients with acute promyelocytic leukaemia (APL) in relapse with chemotherapy, bone marrow transplantation (BMT) or arsenic trioxide (As(2)O(3)) based therapy remains undefined.

PATIENTS AND METHODS

We reviewed the clinical course and treatment outcome of 143 APL cases seen in four major hospitals in Hong Kong over a 10-year period.

RESULTS

Complete remission (CR) was attained in 113 cases (79%) with all-trans retinoic acid (ATRA) and chemotherapy. Relapse occurred at a median of 16 months in 54 cases, with a 3-year disease free survival of 56%. Post-relapse treatment was successful in 41 cases (76%), giving an actuarial 3-year overall survival (OS) of 81% from CR1. Three different protocols were used: chemotherapy alone (n = 19), allogeneic BMT (n = 14) and an As(2)O(3)-based regimen (n = 21). Chemotherapy was associated with the highest treatment-related mortality (TRM) at 53%, giving a CR2 rate of 47%. TRM was 36% for BMT. The CR2 rate for the As(2)O(3)-based regimen was 100%, with no TRM. However, 38% of As(2)O(3) treated patients had subsequent relapses, which were further salvaged in 75% by combined As(2)O(3) plus ATRA. The actuarial OS for the three protocols leveled off by 2 years at 82% for As(2)O(3), 43% for BMT and 23% for chemotherapy (P = 0.0004).

CONCLUSIONS

Our results suggest that As(2)O(3) may be superior to chemotherapy and BMT for the treatment of APL in relapse.

Cytomegalovirus infection associated with clonal proliferation of T-cell large granular lymphocytes: causal or casual?

Clonal proliferation of T-cell large granular lymphocytes (LGL) is an indolent disorder characterized by splenomegaly, lymphocytosis and frequent manifestations of immune disturbances. The LGL are CD3(+) CD4(-) CD8(+) CD56(-). The clonality of the tumor cell population is often only demonstrable by T-cell receptor (TCR) gene rearrangement study because chromosomal abnormality is distinctly rare. We describe a case of T-cell LGL leukemia that presented initially as cytomegalovirus infection. The leukemic LGL are shown to be clonal by both TCR gene rearrangement and chromosomal studies. They persist after subsidence of the cytomegalovirus infection.

Consolidation therapy with autologous blood stem cell transplantation in a patient with primary plasma cell leukaemia

Primary plasma cell leukaemia (PPCL) is a rare form of plasma cell dyscrasia. Conventional melphalan-based treatment is often ineffective, with a reported median survival of 2-7 months only. We report a 53-year-old man with PPCL who was treated with four cycles of combination chemotherapy including vincristine, adriamycin and dexamethasone that resulted in a good partial remission. High-dose melphalan 200 mg/m2 and autologous peripheral blood stem cell (PBSC) rescue was then given 6 months after diagnosis. Maintenance interferon-alpha was started 8 weeks after transplantation with good drug compliance. Complete remission was achieved and molecular remission was documented 11 months after autologous PBSC transplantation. In conclusion, high-dose therapy followed by autologous stem cell rescue is a feasible option for PPCL that can result in a reasonably sustained remission.

A novel t(2;3)(q31;p13) in acute myelocytic leukemia

We report a case of acute myelocytic leukemia without maturation exhibiting a novel t(2;3)(q31;p13). Conventional cytogenetics showed the concomitant occurrence of a single metaphase with 47,XX,+8. Nevertheless, interphase cytogenetics by fluorescence in situ hybridization using a chromosome 8 alpha-satellite DNA probe showed that the percentage of cells with three hybridization signals was within the control range.

Hypoplastic myelodysplastic syndrome-a clinical, morphologic, or genetic diagnosis?

We report a middle-aged female with an 11-year history of nonprogressive pancytopenia and severely hypoplastic marrow with minimal morphologic dysplasia. A diagnosis of hypoplastic myelodysplastic syndrome (MDS) was made because of the finding of a persistent clonal abnormality, del(13)(q12q14), and the subsequent demonstration of a single Auer rod-containing blast in the peripheral blood smear. The case illustrates the problems in the differentiation between aplastic anemia and hypoplastic MDS.

Precursor T-lymphoblastic leukemia with a novel t(1;22)(p34;q13)

A 37-year-old woman that presented with cervical lymphadenopathy and leukocytosis was found to have precursor T-lymphoblastic leukemia (T-ALL). Cytogenetic study of the leukemic cells showed a 46,XX, t(1;22)(p34;q13) karyotype. The t(1;22)(p34;q13) is a novel chromosomal abnormality in human malignancies and is probably a variant form of the t(1;14)(p34;q11) found in precursor T-ALL.

Gain of chromosome 3/3q in B-cell chronic lymphoproliferative disorder is associated with plasmacytoid differentiation with or without IgM overproduction

Trisomy 3 has been reported to be associated with marginal zone B-cell lymphoma. However, its occurrence and significance in other B-cell chronic lymphoproliferative disorders has not been fully defined. We report five cases of B-cell chronic lymphoproliferative disorders showing gain of chromosome 3 or 3q. The patients were elderly males who presented with splenomegaly with or without hepatomegaly and lymphadenopathy. The diagnoses included chronic lymphocytic leukemia (3 cases), prolymphocytic leukemia (1 case), and Waldenstrom macroglobulinemia (1 case). Distinctive feature in this group of patients was the plasmacytoid appearance of the leukemic lymphocytes, with an associated IgM hypergammaglobulinemia in three patients. The relationship between the gain of chromosome 3 and plasmacytoid differentiation in B-cell chronic lymphoproliferative disorders is discussed.

Idiopathic myelofibrosis with extramedullary haemopoiesis involving the urinary bladder in a Chinese lady

Extramedullary haemopoiesis (EMH) associated with idiopathic myelofibrosis most commonly involves the reticuloendothelial organs, such as the spleen and liver, although ectopic haemopoietic tissue has also been described rarely in the lymph nodes, skin, gastrointestinal tract, pleura, peritoneum, central nervous system, and genital and urinary tracts. We report on a 54-year-old Chinese lady with a long history of idiopathic myelofibrosis who presented with gross haematuria and left hydronephrosis due to EMH in the bladder trigone. Cystoscopic examination revealed a sessile necrotic papillary growth at the trigone, obstructing the left ureteric orifice. Transurethral resection of the bladder tumour was performed, and microscopic examination of the tumour chips demonstrated atypical megakaryocytes, immature granulocytes and normoblasts, confirming the presence of EMH. The residual bladder tumour responded well to low dose radiotherapy, with subsequent disappearance of haematuria and normalization of ultrasonogram findings.

Chronic lymphocytic leukemia with a novel der(8;15)(q10;q10) translocation

A 71-year-old male was found to have chronic lymphocytic leukemia. Cytogenetic study of the leukemic lymphocytes shows a 46,XY,der(8;15)+15. The der(8;15) is a novel chromosomal abnormality in human malignancies. The resulting loss of 8p and trisomy 15q are both unusual chromosomal changes in chronic lymphocytic leukemia.

Sinonasal angiosarcoma with marrow involvement at presentation mimicking malignant lymphoma: cytogenetic analysis using multiple techniques

Angiosarcoma of the head and neck most commonly involves the skin of the scalp or face; primary involvement of the sinonasal region is exceedingly rate. We report a patient with sinonasal angiosarcoma who showed marrow involvement at presentation. Marrow aspiration smears showed many large, often segregated blast-like cells, mimicking malignant lymphoma. However, trephine biopsy revealed formation of anastomosing vascular spaces by the tumor cells and immunoreactivity for CD31, supporting a diagnosis of angiosarcoma. DNA ploidy analysis showed an apparent diploidy. Nevertheless, conventional cytogenetics demonstrated very complex chromosomal abnormalities with the presence of multiple hypodiploid clones, together with several near-triploid to near-tetraploid clones showing structural abnormalities involving chromosomes 1, 3, 4, 9, 14, 16, 17, 18, and 22. The identification of these karyotypic changes has been facilitated by the application of comparative genomic hybridization and spectral karyotyping.