Displaying publications 1 - 20 of 33 in total

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  1. Fusion genes in malignant neoplastic disorders of haematopoietic system
    Saleem M, Yusoff NM
    Hematology, 2016 Oct;21(9):501-12.
    PMID: 26871368 DOI: 10.1080/10245332.2015.1106816
    OBJECTIVES: The new World Health Organization's (WHO) classification of haematopoietic and lymphoid tissue neoplasms incorporating the recurrent fusion genes as the defining criteria for different haematopoietic malignant phenotypes is reviewed. The recurrent fusion genes incorporated in the new WHO's classification and other chromosomal rearrangements of haematopoietic and lymphoid tissue neoplasms are reviewed.

    METHODOLOGY: Cytokines and transcription factors in haematopoiesis and leukaemic mechanisms are described. Genetic features and clinical implications due to the encoded chimeric neoproteins causing malignant haematopoietic disorders are reviewed.

    RESULTS AND DISCUSSION: Multiple translocation partner genes are well known for leukaemia such as MYC, MLL, RARA, ALK, and RUNX1. With the advent of more sophisticated diagnostic tools and bioinformatics algorithms, an exponential growth in fusion genes discoveries is likely to increase.

    CONCLUSION: Demonstration of fusion genes and their specific translocation breakpoints in malignant haematological disorders are crucial for understanding the molecular pathogenesis and clinical phenotype of cancer, determining prognostic indexes and therapeutic responses, and monitoring residual disease and relapse status.

    Matched MeSH terms: Lymphoma/genetics*
  2. Fulltext Double Philadelphia chromosome-positive B acute lymphoblastic leukaemia in an elderly patient
    Tang YL, Raja Sabudin RZ, Leong CF, Ko CC, Chia WK, Salwati S, et al.
    Malays J Pathol, 2015 Dec;37(3):275-9.
    PMID: 26712675 MyJurnal
    A rare case of double Philadelphia chromosome-positive B Acute lymphoblastic Leukaemia (B-ALL) is reported here. A 60-year-old lady presented with one month history of fever, submandibular lymphadenopathy, loss of appetite and weight loss. Physical examination revealed multiple palpable cervical lymph nodes. Blood film showed leucocytosis with 72% blasts. Bone marrow assessment confirmed a diagnosis of B-ALL with presence of double Philadelphia (Ph) chromosomes. As she was very ill, she was initially treated with an attenuated regimen of induction chemotherapy consisting of rituximab, cyclophosphamide, vincristine and prednisolone (R-CVP) along with intrathecal chemotherapy comprising methotrexate, cytarabine and hydrocortisone. Bone marrow examination post-induction chemotherapy showed >5% blasts. She was subsequently re-induced with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP) along with intrathecal chemotherapy, following which she went into complete remission. Consolidation chemotherapy consisting of methotrexate, methylprednisolone, cytarabine, intrathecal chemotherapy and imatinib was subsequently administered followed by maintenance chemotherapy consisting of vincristine, prednisolone and imatinib (IDEAMOP). She developed spontaneous bruises and relapsed four months into her maintenance chemotherapy with 90% blasts in the bone marrow which was treated with fludarabine, cytarabine and granulocyte colony stimulating factor (FLAG). Unfortunately she developed neutropenic sepsis which was complicated by invasive lung aspergillosis. Bone marrow examination post-FLAG showed 80% blasts. Despite aggressive antifungal therapy, her lung infection worsened and she finally succumbed to her illness 13 months after the initial diagnosis. We highlight a rare case of elderly B-ALL with double Ph chromosomes which carries a poor prognosis despite aggressive treatment for the disease and its complications.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  3. Fulltext Concordant childhood acute lymphoblastic leukemia in monozygotic twins
    Chin YM, Wan Ariffin A, Lin HP, Chan YS
    Med J Malaysia, 1996 Mar;51(1):145-8.
    PMID: 10967997
    Two 4-year-old monozygotic Chinese, female twins developed concordant childhood acute lymphoblastic leukemia (ALL) within an interval of about 2 weeks. Based on morphology and cytochemistry findings of the bone marrow blast cells, a diagnosis of ALL, L1 was made. Immunophenotyping showed the blast cells of both twins expressed similar antigens, i.e. HLA-DR, CD10, CD13, CD19, CD22 and CD34. Identical blood group, same HLA (human leucocyte antigen) genotype, sex and similar appearance suggest that the twins are monozygotic. Since the bone marrow leukemic cells of both twins were identical in morphology and expressed the same antigens with almost similar percentages of positivity, it is likely that the blast cells were derived from the same single clone. Based on the single clone hypothesis, the leukemogenic event must have arisen in utero in one twin and the cells from the abnormal clone then spread to the other twin via shared placental anastomoses.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  4. Association of ARID5B gene variants with acute lymphoblastic leukemia in Yemeni children
    Al-Absi B, Noor SM, Saif-Ali R, Salem SD, Ahmed RH, Razif MF, et al.
    Tumour Biol., 2017 Apr;39(4):1010428317697573.
    PMID: 28381164 DOI: 10.1177/1010428317697573
    Studies have shown an association between ARID5B gene polymorphisms and childhood acute lymphoblastic leukemia. However, the association between ARID5B variants and acute lymphoblastic leukemia among the Arab population still needs to be studied. The aim of this study was to investigate the association between ARID5B variants with acute lymphoblastic leukemia in Yemeni children. A total of 14 ARID5B gene single nucleotide polymorphisms (SNPs) were genotyped in 289 Yemeni children, of whom 136 had acute lymphoblastic leukemia and 153 were controls, using the nanofluidic Dynamic Array (Fluidigm 192.24 Dynamic Array). Using logistic regression adjusted for age and gender, the risks of acute lymphoblastic leukemia were presented as odds ratios and 95% confidence intervals. We found that nine SNPs were associated with acute lymphoblastic leukemia under additive genetic models: rs7073837, rs10740055, rs7089424, rs10821936, rs4506592, rs10994982, rs7896246, rs10821938, and rs7923074. Furthermore, the recessive models revealed that six SNPs were risk factors for acute lymphoblastic leukemia: rs10740055, rs7089424, rs10994982, rs7896246, rs10821938, and rs7923074. The gender-specific impact of these SNPs under the recessive genetic model revealed that SNPs rs10740055, rs10994982, and rs6479779 in females, and rs10821938 and rs7923074 in males were significantly associated with acute lymphoblastic leukemia risk. Under the dominant model, SNPs rs7073837, rs10821936, rs7896246, and rs6479778 in males only showed striking association with acute lymphoblastic leukemia. The additive model revealed that SNPs with significant association with acute lymphoblastic leukemia were rs10821936 (both males and females); rs7073837, rs10740055, rs10994982, and rs4948487 (females only); and rs7089424, rs7896246, rs10821938, and rs7923074 (males only). In addition, the ARID5B haplotype block (CGAACACAA) showed a higher risk for acute lymphoblastic leukemia. The haplotype (CCCGACTGC) was associated with protection against acute lymphoblastic leukemia. In conclusion, our study has shown that ARID5B variants are associated with acute lymphoblastic leukemia in Yemeni children with several gender biases of ARID5B single nucleotide polymorphisms reported.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  5. CD3-positive plasmablastic lymphoma reported in two cases: A potential diagnostic caveat
    Wong YP, Masir N, Chew MX
    Indian J Pathol Microbiol, 2021 8 4;64(3):579-583.
    PMID: 34341278 DOI: 10.4103/IJPM.IJPM_616_20
    Plasmablastic lymphoma (PBL) is a rare aggressive subtype of mature large B cell lymphoma involving almost exclusively the extranodal regions particularly the oral cavity, frequently described in immunocompromised patients. PBL is characterized histologically by diffuse proliferation of large neoplastic cells resembling B immunoblasts or plasmablasts. The diagnosis of PBL can be difficult due to its ambiguous histopathological features mimicking most large cell lymphomas and lacking a distinctive immunophenotypic pattern. They typically lack expression of CD20 and CD79a but may express plasma cell marker, CD138. Aberrant immunoexpression of CD3, a T-cell marker in PBL in the absence of other B-cell markers is exceptionally rare, may potentially lead to incorrect interpretation. Herein, we report a case series of CD3-positive PBL of oral cavity in two individuals, which were initially misdiagnosed as high-grade T-cell lymphomas including extranodal NK/T-cell lymphoma, nasal type. Useful distinguishing clinical settings, histomorphological features, immunohistochemistry and molecular expression profiles of PBL are discussed.
    Matched MeSH terms: Plasmablastic Lymphoma/genetics*
  6. Fulltext Validation of a multiplex RT-PCR assay for screening significant oncogene fusion transcripts in children with acute lymphoblastic leukaemia
    Ariffin H, Chen SP, Wong HL, Yeoh A
    Singapore Med J, 2003 Oct;44(10):517-20.
    PMID: 15024455
    In childhood acute lymphoblastic leukaemia (ALL), cytogenetics play an important role in diagnosis, allocation of treatment and prognosis. Conventional cytogenetic analysis, involving mainly karyotyping in our experience, has not been successful in a large proportion of cases due to inadequate metaphase spreads and poor chromosome morphology. Our aim is to develop a highly sensitive and specific method to screen simultaneously for the four most frequent fusion transcripts resulting from specific chromosomal translocations, namely, both the CML- and ALLtype BCR-ABL transcripts of t(9;22), E2A-PBX1 transcript of t(1;19), the MLL-AF4 transcript of t(4;11) and TEL-AML1 (also termed ETV6-CBFA2) of the cryptic t(12;21). A multiplex reverse transcription polymerase chain reaction protocol (RT-PCR) was developed and tested out on archival bone marrow samples and leukaemia cell lines. In all samples with a known translocation detected by cytogenetic techniques, the same translocation was identified by the multiplex-PCR assay. Multiplex RT-PCR assay is an effective, sensitive, accurate and cost-effective diagnostic tool which can improve our ability to accurately and rapidly risk-stratify patients with childhood ALL.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  7. Transcriptional landscape of B cell precursor acute lymphoblastic leukemia based on an international study of 1,223 cases
    Li JF, Dai YT, Lilljebjörn H, Shen SH, Cui BW, Bai L, et al.
    Proc Natl Acad Sci U S A, 2018 12 11;115(50):E11711-E11720.
    PMID: 30487223 DOI: 10.1073/pnas.1814397115
    Most B cell precursor acute lymphoblastic leukemia (BCP ALL) can be classified into known major genetic subtypes, while a substantial proportion of BCP ALL remains poorly characterized in relation to its underlying genomic abnormalities. We therefore initiated a large-scale international study to reanalyze and delineate the transcriptome landscape of 1,223 BCP ALL cases using RNA sequencing. Fourteen BCP ALL gene expression subgroups (G1 to G14) were identified. Apart from extending eight previously described subgroups (G1 to G8 associated with MEF2D fusions, TCF3-PBX1 fusions, ETV6-RUNX1-positive/ETV6-RUNX1-like, DUX4 fusions, ZNF384 fusions, BCR-ABL1/Ph-like, high hyperdiploidy, and KMT2A fusions), we defined six additional gene expression subgroups: G9 was associated with both PAX5 and CRLF2 fusions; G10 and G11 with mutations in PAX5 (p.P80R) and IKZF1 (p.N159Y), respectively; G12 with IGH-CEBPE fusion and mutations in ZEB2 (p.H1038R); and G13 and G14 with TCF3/4-HLF and NUTM1 fusions, respectively. In pediatric BCP ALL, subgroups G2 to G5 and G7 (51 to 65/67 chromosomes) were associated with low-risk, G7 (with ≤50 chromosomes) and G9 were intermediate-risk, whereas G1, G6, and G8 were defined as high-risk subgroups. In adult BCP ALL, G1, G2, G6, and G8 were associated with high risk, while G4, G5, and G7 had relatively favorable outcomes. This large-scale transcriptome sequence analysis of BCP ALL revealed distinct molecular subgroups that reflect discrete pathways of BCP ALL, informing disease classification and prognostic stratification. The combined results strongly advocate that RNA sequencing be introduced into the clinical diagnostic workup of BCP ALL.
    Matched MeSH terms: Precursor B-Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  8. Fulltext Whole-genome noncoding sequence analysis in T-cell acute lymphoblastic leukemia identifies oncogene enhancer mutations
    Hu S, Qian M, Zhang H, Guo Y, Yang J, Zhao X, et al.
    Blood, 2017 Jun 15;129(24):3264-3268.
    PMID: 28408461 DOI: 10.1182/blood-2017-03-771162
    Publisher's Note: There is an Inside Blood Commentary on this article in this issue.
    Matched MeSH terms: Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  9. Fulltext Host genetic variants of ABCB1 and IL15 influence treatment outcome in paediatric acute lymphoblastic leukaemia
    Lu Y, Kham SK, Ariffin H, Oei AM, Lin HP, Tan AM, et al.
    Br. J. Cancer, 2014 Mar 18;110(6):1673-80.
    PMID: 24434428 DOI: 10.1038/bjc.2014.7
    Host germline variations and their potential prognostic importance is an emerging area of interest in paediatric ALL.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  10. Genetic susceptibility to childhood acute lymphoblastic leukemia shows protection in Malay boys: results from the Malaysia-Singapore ALL Study Group
    Yeoh AE, Lu Y, Chan JY, Chan YH, Ariffin H, Kham SK, et al.
    Leuk. Res., 2010 Mar;34(3):276-83.
    PMID: 19651439 DOI: 10.1016/j.leukres.2009.07.003
    To study genetic epidemiology of childhood acute lymphoblastic leukemia (ALL) in the Chinese and Malays, we investigated 10 polymorphisms encoding carcinogen- or folate-metabolism and transport. Sex-adjusted analysis showed NQO1 609CT significantly protects against ALL, whilst MTHFR 677CT confers marginal protection. Interestingly, we observed that NQO1 609CT and MTHFR 1298 C-allele have greater genetic impact in boys than in girls. The combination of SLC19A1 80GA heterozygosity and 3'-TYMS -6bp/-6bp homozygous deletion is associated with reduced ALL risk in Malay boys. Our study has suggested the importance of gender and race in modulating ALL susceptibility via the folate metabolic pathway.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  11. Heterogeneous t(4;11) fusion transcripts in two infants with acute lymphoblastic leukemia
    Gill HK, Ten SK, Dhaliwal JS, Moore S, Hassan R, Karim FA, et al.
    Malays J Pathol, 2004 Dec;26(2):105-10.
    PMID: 16329562
    An RT-PCR assay detected the t(4;11) translocation in two infants with acute lymphoblastic leukemia (ALL). Case P76 was a 10-month-old, female infant, who presented with a WBC of 137.4 x 10(9)/l and a pre-pre-B ALL immunophenotype. Case P120 was a 6-month-old female infant, with a WBC > 615 x 10(9)/l and a pre-pre-B ALL immunophenotype. RT-PCR of cDNA from both these cases generated a 656 bp and a 542 bp respectively, which sequencing confirmed as t(4;11) fusion transcripts. The primers and conditions selected for this assay are compatible with a one-step multiplex PCR for the main translocations in childhood ALL.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  12. TEL-AML1 frequency in multi-ethnic Malaysian pediatric acute lymphoblastic leukemia
    Gill HK, Keoh TS, Dhaliwal JS, Moore S, Kim TS, Hassan R, et al.
    Cancer Genet. Cytogenet., 2005 Jan 15;156(2):129-33.
    PMID: 15642392
    Eighty-eight multi-ethnic Malaysian pediatric acute lymphoblastic leukemia (ALL) patients were screened for the TEL-AML1 rearrangement by reverse transcription-polymerase chain reaction (RT-PCR). Fluorescence in situ hybridization (FISH) was used as an independent screen for 30 cases and to confirm RT-PCR positive cases. Seventeen patients, or 19%, were found to be t(12;21) positive. Ethnically the group comprised 12 Malays, 4 Chinese, and 1 Indian. All patients, including 1 with an unusual blast cell morphology who suffered an early relapse and death, were characteristic TEL-AML1 cases in cell count, age, ALL subset classification, and fusion transcript expressed. This study shows that in Malaysia, TEL-AML1 is found in the same distinct ALL subset and at a similar frequency as in other diverse childhood ALL cohorts.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  13. Fulltext Breakpoint cluster region (BCR) gene rearrangement studies in chronic myeloid and acute lymphoblastic leukemias
    Chin YM, Bosco JJ, Koh CL
    Med J Malaysia, 1992 Jun;47(2):110-3.
    PMID: 1494330
    Deoxyribonucleic acid (DNA) of twenty chronic myeloid leukemia (CML) and thirty acute lymphoblastic leukemia (ALL) patients were analysed by Southern hybridization. The DNA was digested with BglII and hybridized with a 4.5-kilobase (kb) ph1/bcr-3 DNA probe. All the 20 CML patients showed gene rearrangement within a 5.8-kb segment (the major breakpoint cluster region, M-bcr) of the breakpoint cluster region (bcr) gene of chromosome 22, indicating the presence of the Philadelphia chromosome. M-bcr rearrangement at the bcr gene of chromosome twenty-two was not detected in all the thirty ALL patients (nine adults and twenty-one children) and two normal controls.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  14. Fulltext Meta-analysis of gene expression in relapsed childhood B-acute lymphoblastic leukemia
    Chow YP, Alias H, Jamal R
    BMC Cancer, 2017 02 10;17(1):120.
    PMID: 28183295 DOI: 10.1186/s12885-017-3103-1
    BACKGROUND: Relapsed pediatric B-acute lymphoblastic leukemia (B-ALL) remains as the leading cause of cancer death among children. Other than stem cell transplantation and intensified chemotherapy, no other improved treatment strategies have been approved clinically. Gene expression profiling represents a powerful approach to identify potential biomarkers and new therapeutic targets for various diseases including leukemias. However, inadequate sample size in many individual experiments has failed to provide adequate study power to yield translatable findings. With the hope of getting new insights into the biological mechanisms underpinning relapsed ALL and identifying more promising biomarkers or therapeutic targets, we conducted a meta-analysis of gene expression studies involving ALL from 3 separate studies.

    METHOD: By using the keywords "acute lymphoblastic leukemia", and "microarray", a total of 280 and 275 microarray datasets were found listed in Gene Expression Omnibus database GEO and ArrayExpress database respectively. Further manual inspection found that only three studies (GSE18497, GSE28460, GSE3910) were focused on gene expression profiling of paired diagnosis-relapsed pediatric B-ALL. These three datasets which comprised of a total of 108 matched diagnosis-relapsed pediatric B-ALL samples were then included for this meta-analysis using RankProd approach.

    RESULTS: Our analysis identified a total of 1795 upregulated probes which corresponded to 1527 genes (pfp  1), and 1493 downregulated probes which corresponded to 1214 genes (pfp 

    Matched MeSH terms: Precursor B-Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  15. Intensifying Treatment of Childhood B-Lymphoblastic Leukemia With IKZF1 Deletion Reduces Relapse and Improves Overall Survival: Results of Malaysia-Singapore ALL 2010 Study
    Yeoh AEJ, Lu Y, Chin WHN, Chiew EKH, Lim EH, Li Z, et al.
    J Clin Oncol, 2018 09 10;36(26):2726-2735.
    PMID: 30044693 DOI: 10.1200/JCO.2018.78.3050
    Purpose Although IKZF1 deletion ( IKZF1del) confers a higher risk of relapse in childhood B-cell acute lymphoblastic leukemia (B-ALL), it is uncertain whether treatment intensification will reverse this risk and improve outcomes. The Malaysia-Singapore ALL 2010 study (MS2010) prospectively upgraded the risk assignment of patients with IKZF1del to the next highest level and added imatinib to the treatment of all patients with BCR- ABL1 fusion. Patients and Methods In total, 823 patients with B-ALL treated in the Malyasia-Singapore ALL 2003 study (MS2003; n = 507) and MS2010 (n = 316) were screened for IKZF1del using the multiplex ligation-dependent probe amplification assay. The impact of IKZF1del on the 5-year cumulative incidence of relapse (CIR) was compared between the two studies. Results Patient characteristics were similar in both cohorts, including IKZF1del frequencies (59 of 410 [14.4%] v 50 of 275 [18.2%]; P = .2). In MS2003, where IKZF1del was not used in risk assignment, IKZF1del conferred a significantly higher 5-year CIR (30.4% v 8.1%; P = 8.7 × 10-7), particularly in the intermediate-risk group who lacked high-risk features (25.0% v 7.5%; P = .01). For patients with BCR-ABL1-negative disease, IKZF1del conferred a higher 5-year CIR (20.5% v 8.0%; P = .01). In MS2010, the 5-year CIR of patients with IKZF1del significantly decreased to 13.5% ( P = .05) and no longer showed a significant difference in patients with BCR-ABL1-negative disease (11.4% v 4.4%; P = .09). The 5-year overall survival for patients with IKZF1del improved from 69.6% in MS2003 to 91.6% in MS2010 ( P = .007). Conclusion Intensifying therapy for childhood B-ALL with IKZF1del significantly reduced the risk of relapse and improved overall survival. Incorporating IKZF1del screening significantly improved treatment outcomes in contemporary ALL therapy.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  16. Identifying IGH disease clones for MRD monitoring in childhood B-cell acute lymphoblastic leukemia using RNA-Seq
    Li Z, Jiang N, Lim EH, Chin WHN, Lu Y, Chiew KH, et al.
    Leukemia, 2020 09;34(9):2418-2429.
    PMID: 32099036 DOI: 10.1038/s41375-020-0774-4
    Identifying patient-specific clonal IGH/TCR junctional sequences is critical for minimal residual disease (MRD) monitoring. Conventionally these junctional sequences are identified using laborious Sanger sequencing of excised heteroduplex bands. We found that the IGH is highly expressed in our diagnostic B-cell acute lymphoblastic leukemia (B-ALL) samples using RNA-Seq. Therefore, we used RNA-Seq to identify IGH disease clone sequences in 258 childhood B-ALL samples for MRD monitoring. The amount of background IGH rearrangements uncovered by RNA-Seq followed the Zipf's law with IGH disease clones easily identified as outliers. Four hundred and ninety-seven IGH disease clones (median 2, range 0-7 clones/patient) are identified in 90.3% of patients. High hyperdiploid patients have the most IGH disease clones (median 3) while DUX4 subtype has the least (median 1) due to the rearrangements involving the IGH locus. In all, 90.8% of IGH disease clones found by Sanger sequencing are also identified by RNA-Seq. In addition, RNA-Seq identified 43% more IGH disease clones. In 69 patients lacking sensitive IGH targets, targeted NGS IGH MRD showed high correlation (R = 0.93; P = 1.3 × 10-14), better relapse prediction than conventional RQ-PCR MRD using non-IGH targets. In conclusion, RNA-Seq can identify patient-specific clonal IGH junctional sequences for MRD monitoring, adding to its usefulness for molecular diagnosis in childhood B-ALL.
    Matched MeSH terms: Precursor B-Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  17. Fulltext Minimal residual disease-guided treatment deintensification for children with acute lymphoblastic leukemia: results from the Malaysia-Singapore acute lymphoblastic leukemia 2003 study
    Yeoh AE, Ariffin H, Chai EL, Kwok CS, Chan YH, Ponnudurai K, et al.
    J Clin Oncol, 2012 Jul 1;30(19):2384-92.
    PMID: 22614971 DOI: 10.1200/JCO.2011.40.5936
    PURPOSE: To improve treatment outcome for childhood acute lymphoblastic leukemia (ALL), we designed the Malaysia-Singapore ALL 2003 study with treatment stratification based on presenting clinical and genetic features and minimal residual disease (MRD) levels measured by polymerase chain reaction targeting a single antigen-receptor gene rearrangement.
    PATIENTS AND METHODS: Five hundred fifty-six patients received risk-adapted therapy with a modified Berlin-Frankfurt-Münster-ALL treatment. High-risk ALL was defined by MRD ≥ 1 × 10(-3) at week 12 and/or poor prednisolone response, BCR-ABL1, MLL gene rearrangements, hypodiploid less than 45 chromosomes, or induction failure; standard-risk ALL was defined by MRD ≤ 1 × 10(-4) at weeks 5 and 12 and no extramedullary involvement or high-risk features. Intermediate-risk ALL included all remaining patients.
    RESULTS: Patients who lacked high-risk presenting features (85.7%) received remission induction therapy with dexamethasone, vincristine, and asparaginase, without anthracyclines. Six-year event-free survival (EFS) was 80.6% ± 3.5%; overall survival was 88.4% ± 3.1%. Standard-risk patients (n = 172; 31%) received significantly deintensified subsequent therapy without compromising EFS (93.2% ± 4.1%). High-risk patients (n = 101; 18%) had the worst EFS (51.8% ± 10%); EFS was 83.6% ± 4.9% in intermediate-risk patients (n = 283; 51%).
    CONCLUSION: Our results demonstrate significant progress over previous trials in the region. Three-drug remission-induction therapy combined with MRD-based risk stratification to identify poor responders is an effective strategy for childhood ALL.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics
  18. Ethnic differences in the frequency of subtypes of childhood acute lymphoblastic leukemia: results of the Malaysia-Singapore Leukemia Study Group
    Ariffin H, Chen SP, Kwok CS, Quah TC, Lin HP, Yeoh AE
    J Pediatr Hematol Oncol, 2007 Jan;29(1):27-31.
    PMID: 17230064
    Childhood acute lymphoblastic leukemia (ALL) is clinically heterogeneous with prognostically and biologically distinct subtypes. Although racial differences in frequency of different types of childhood ALL have been reported, many are confounded by selected or limited population samples. The Malaysia-Singapore (MA-SPORE) Leukemia Study Group provided a unique platform for the study of the frequency of major subgroups of childhood ALL in a large cohort of unselected multiethnic Asian children. Screening for the prognostically important chromosome abnormalities (TEL-AML1, BCR-ABL, E2A-PBX1, and MLL) using multiplex reverse-transcription polymerase chain reaction was performed on 299 consecutive patients with ALL at 3 study centers (236 de novo, 63 at relapse), with the ethnic composition predominantly Chinese (51.8%) and Malay (34.8%). Reverse-transcription polymerase chain reaction was successful in 278 (93%) of cases screened. The commonest fusion transcript was TEL-AML1 (19.1%) followed by BCR-ABL (7.8%), MLL rearrangements (4.2%), and E2A-PBX1 (3.1%). Chinese have a significantly lower frequency of TEL-AML1 (13.3% in de novo patients) compared with Malays (22.2%) and Indians (21.7%) (P=0.04). Malays have a lower frequency of T-ALL (6.2%) compared with the Chinese and Indians (9.8%). Both Malays (7.4%) and Chinese (5.0%) have significantly higher frequency of BCR-ABL compared with the Indian population (P<0.05) despite a similar median age at presentation. Our study suggests that there are indeed significant and important racial differences in the frequency of subtypes of childhood ALL. Comprehensive subgrouping of childhood ALL may reveal interesting population frequency differences of the various subtypes, their risk factors and hopefully, its etiology.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics
  19. Thiopurine methyltransferase polymorphisms in a multiracial asian population and children with acute lymphoblastic leukemia
    Kham SK, Tan PL, Tay AH, Heng CK, Yeoh AE, Quah TC
    J Pediatr Hematol Oncol, 2002 Jun-Jul;24(5):353-9.
    PMID: 12142782
    The purpose of this study was to determine the frequency of thiopurine methyltransferase (TPMT) polymorphisms in a multiracial Asian population and to assess its relevance in the management of childhood acute lymphoblastic leukemia (ALL). Six hundred unrelated cord blood samples from 200 Chinese, Malay, and Indian healthy newborns were collected at the National University Hospital, Singapore; an additional 100 children with ALL were analyzed for five of the commonly reported TPMT variant alleles using polymerase chain reaction/restriction fragment length polymorphism and allele-specific polymerase chain reaction-based assays. In the cord blood study, the TPMT*3C variant was detected in all three ethnic groups; Chinese, Malays, and Indians had allele frequencies of 3%, 2.3%, and 0.8%, respectively. The TPMT*3A variant was found only among the Indians at a low allele frequency of 0.5%. The TPMT*6 variant was found in one Malay sample. Among the children with ALL, two white and one Chinese were heterozygous for the TPMT*3A variant and showed intermediate sensitivity to 6-mercaptopurine during maintenance therapy. Three Chinese patients and one Malay patient were heterozygous for the TPMT*3C variant. Mercaptopurine sensitivity could be validated in only one out of four TPMT*3C heterozygous patients. The overall allele frequency of the TPMT variants in this multiracial population was 2.5%. The TPMT*3C was the most common variant allele; TPMT*3A and TPMT*6 were rare. These results support the feasibility of performing TPMT genotyping in all children diagnosed with acute leukemia to minimize toxicity from thiopurine chemotherapy.
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  20. Mature B-cell acute lymphoblastic leukaemia associated with a rare MLL-FOXO4 fusion gene
    Lim L, Chen KS, Krishnan S, Gole L, Ariffin H
    Br J Haematol, 2012 Jun;157(6):651.
    PMID: 22429121 DOI: 10.1111/j.1365-2141.2012.09091.x
    Matched MeSH terms: Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
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