Ping Chong Bee

A man with concomitant polycythaemia vera and chronic myeloid leukemia: the dynamics of the two disorders

The co-occurrence of JAK2 V617F mutation with BCR-ABL reciprocal translocation is uncommon. We report a 60-year-old man who initially presented with phenotype of polycythemia vera (PV), which evolved into chronic myeloid leukemia and back to PV once treatment with imatinib was commenced. JAK2 V617F mutation and BCR-ABL fusion transcripts were detected in the initial sample. However, JAK2 V617F alleles diminished when BCR-ABL mRNA burden increased and reappeared once the patient was commenced on imatinib. The dynamic interaction between JAK2 V617F and BCR-ABL implies that two independent clones exist with the JAK2 V617F clone only achieving clonal dominance when BCR-ABL positive clones are suppressed by imatinib.

Effect of polymorphisms within methotrexate pathway genes on methotrexate toxicity and plasma levels in adults with hematological malignancies

AIM Pharmacogenetics of methotrexate (MTX) contributes to interindividual differences in toxicity. We aimed to evaluate the impact of SNPs within the MTX pathway genes on MTX-induced toxicity and MTX plasma levels at 48 h following treatment in Asian adults with acute lymphoblastic leukemia or non-Hodgkin lymphoma. PATIENTS & METHODS Patients (n = 71) were genotyped for MTHFR C677T, MTHFR A1298C, SLC19A1 G80A, ABCG2 C421A and ABCB1 C3435T using the Sequenom MassARRAY platform. Plasma MTX concentrations at 48 h were measured by fluorescence polarization immunoassay. RESULTS Forty-eight patients had hematopoietic toxicity, 51 had hepatic toxicity and 36 had mucositis. Patients homozygous for MTHFR 677TT were associated with increased risk of both hematopoietic (odds ratio [OR]: 9.03; 95% CI: 2.28-36.16; p = 0.002) and hepatic (OR: 3.92; 95% CI: 1.01-15.11; p = 0.036) toxicities. Hepatic toxicity was associated with SLC19A1 G80A (OR: 5.27, 95% CI: 1.21-22.72; p = 0.032) and ABCB1 C3435T (OR: 8.62; 95% CI: 1.96-37.57; p = 0.004). However, polymorphisms in MTHFR A1298C and ABCG2 C421A were not associated with any of the toxicities, and mucositis was not associated with any polymorphisms of the MTX pathway genes. Patients with MTHFR C677T and ABCB1 C3435T polymorphisms appear to have significantly higher MTX plasma concentrations (p < 0.05). CONCLUSION Our results in Asian adults provides evidence for the contribution pharmacogenetics to the toxicity of high-dose MTX and plasma MTX concentrations at 48 h following treatment in patients with acute lymphoblastic leukemia or non-Hodgkin lymphoma. These results will contribute towards the effort of MTX therapy individualization.

Myeloid Sarcoma: An Unusual Presentation of Acute Promyelocytic Leukemia Causing Spinal Cord Compression

Acute promyelocytic leukemia with concurrent myeloid sarcoma is a rare clinical event. Herein we describe a patient that presented with back pain and bilateral leg weakness caused by spinal cord compression due to extramedullary deposition of leukemic cells. Acute promyelocytic leukemia was suspected based on immunophenotypic findings of malignant cells in bone marrow aspirate. The diagnosis was confirmed by the presence of PML-RARα fusion copies. MRI showed multiple hyperintense changes on the vertebral bodies, together with intraspinal masses causing spinal cord compression. The patient immediately underwent radiotherapy, and was treated with all-trans retinoic acid and idarubicin. Reassessment MRI showed complete resolution of all intraspinal masses and the disappearance of most of the bony lesions. Post-treatment bone marrow aspirate showed complete hematological and molecular remission. The motor power of his legs fully recovered from 0/5 to 5/5; however, sensory loss below the T4 level persisted.

Identification of copy number alterations by array comparative genomic hybridization in patients with late chronic or accelerated phase chronic myeloid leukemia treated with imatinib mesylate

The outcome of treating chronic myeloid leukemia (CML) with imatinib mesylate (IM) is inferior when therapy is commenced in late chronic or accelerated phase as compared to early chronic phase. This may be attributed to additional genomic alterations that accumulate during disease progression. We sought to identify such lesions in patients showing suboptimal response to IM by performing array-CGH analysis on 39 sequential samples from 15 CML patients. Seventy-four cumulative copy number alterations (CNAs) consisting of 35 losses and 39 gains were identified. Alterations flanking the ABL1 and BCR genes on chromosomes 9 and 22, respectively, were the most common identified lesions with 5 patients losing variable portions of 9q34.11 proximal to ABL1. Losses involving 1p36, 5q31, 17q25, Y and gains of 3q21, 8q24, 22q11, Xp11 were among other recurrent lesions identified. Aberrations were also observed in individual patients, involving regions containing known leukemia-associated genes; CDKN2A/2B, IKZF1, RB1, TLX1, AFF4. CML patients in late stages of their disease, harbor pre-existing and evolving sub-microscopic CNAs that may influence disease progression and IM response.

Analysis of interleukin-10 promoter single nucleotide polymorphisms and risk of non-Hodgkin lymphoma in a Malaysian population.

Abstract We evaluated the association of two IL10 single nucleotide polymorphisms (SNPs) (rs1800896 and rs1800871) with non-Hodgkin lymphoma (NHL) risk in the three major races of the Malaysian population (Malay, Chinese and Indian; 317 cases and 330 controls). Our initial screening demonstrated that rs1800871 but not rs1800896 was significantly associated with increased NHL risk in Malays (pMalay-Rec = 0.007) and Chinese only (pChinese-Rec = 0.039). Subsequent combined analysis of the Malay and Chinese revealed significant association of rs1800871 with all (ALL) NHL subtypes (pMeta-ALL-NHL-Rec = 0.001), ALL B-cell subtypes (pMeta-ALL-B-cell-Rec = 0.003), diffuse large B-cell lymphoma (DLBCL) subtype (pMeta-DLBCL-Rec = 0.002) and ALL T-cell subtypes (pMeta-ALL-T-cell-Rec = 0.031). SNP rs1800896 showed increased risk only in follicular lymphoma (FL) (pMeta-FL-Dom = 0.0004). We also detected a male-specific association of rs1800871 with increased NHL risk (pMeta-Male-ALL-NHL-Rec = 0.006) in the combined analysis. To our knowledge, this is the first report on the association of IL10 promoter SNPs with NHL susceptibility in the three major races of Malaysia.

Polymorphisms in methylenetetrahydrofolate reductase gene and risk of non-Hodgkin lymphoma in a multi-ethnic population

An imbalance in folate metabolism can adversely affect DNA synthesis and methylation systems which can lead to susceptibility to non-Hodgkin lymphoma (NHL). Whether single nucleotide polymorphisms (SNPs) and their haplotypes in the methylenetetrahydrofolate reductase (MTHFR) are associated with NHL, remain inconclusive. We investigated the association between MTHFR C677T and A1298C SNPs and NHL risk in a population which is made up of Malay, Chinese and Indian ethnic subgroups. A total of 372 NHL patients and 722 controls were genotyped using the Sequenom MassARRAY platform. Our results of the pooled subjects failed to demonstrate significant association between the MTHFR C677T and A1298C SNPs with NHL and its subtypes. The results were in agreement with the previous meta-analyses. In the Indian ethnic subgroup however, single locus analysis of MTHFR A1298C appears to confer risk to NHL (Odds ratio (OR) 1.91, 95% confidence interval (95% CI) 1.22–3.00, P=0.006). The risk is almost doubled in homozygous carrier of MTHFR 1298CC (OR 4.03, 95% CI 1.56–10.43, P=0.004). Haplotype analysis revealed higher frequency of CC in the Indian NHL patients compared with controls (OR 1.86, 95% CI 1.18–2.93, P=0.007). There is lack of evidence to suggest an association between MTHFR C677T and A1298C with the risk of NHL in the Malays and Chinese. In the Indians however, the MTHFR A1298C confers risk to NHL. This study suggests ethnicity modifies the relationship between polymorphisms in the folate-metabolizing gene and NHL.

Acquired Factor VIII Inhibitors: Three Cases.

Acquired hemophilia A is a rare, but devastating bleeding disorder caused by spontaneous development of autoantibodies directed against coagulation factor VIII. In 40%-50% of patients it is associated with such conditions as the postpartum period, malignancy, use of medications, and autoimmune diseases; however, its cause is unknown in most cases. Acquired hemophilia A should be suspected in patients that present with a coagulation abnormality, and a negative personal and family history of bleeding. Herein we report 3 patients with acquired hemophilia A that had different underlying pathologies, clinical presentations, and therapeutic responses. Factor VIII inhibitor formation in case 1 occurred 6 months after giving birth; underlying disorders were not identified in cases 2 or 3. The bleeding phenotype in these patients’ ranged from no bleeding tendency with isolated prolongation of APTT (activated partial thromboplastin time) to severe intramuscular hematoma and hemarthrosis necessitating recombinant activated factor VII infusion and blood components transfusion. Variable responses to immunosuppressive treatment were also observed. Conflict of interest:None declared.

A Case of T-Cell Acute Lymphoblastic Leukemia after Treatment of Acute Promyelocytic Leukemia

We diagnosed T-cell acute lymphoblastic leukemia (T-ALL) with multiple cytogenetic abnormalities in a 17-year-old girl a year after she had received a diagnosis of acute promyelocytic leukemia (APML). After the diagnosis of APML in June 2001, the patient was treated with idarubicin and all-trans-retinoic acid. In September 1999, her younger sister also received a diagnosis of APML and to date has remained well. T-ALL after remission of APML is very rare, and only 1 such case has been reported. Possible causes include therapy-related reasons, genetic susceptibility to leukemia, and environmental exposure.

Survey of willingness to accept chemotherapy among elderly Malaysian patients.

BACKGROUND The geriatric population in Malaysia is predicted to increase from 4% of the total population in 1998 to 9.8% by 2020, in parallel with developments in the socioeconomy. Cancer is expected to be a major medical issue among this population. However, the decision for treatment in Malaysia is always decided by the caregivers instead of the elderly patients themselves. OBJECTIVE The aim of the study was to assess the willingness to accept chemotherapy among elderly Malaysians. MATERIALS AND METHODS In this cross-sectional study, patients aged 60 and above from various clinics/wards were recruited. Those giving consent were interviewed using a questionnaire. RESULTS A total of 75 patients were recruited, 35 patients (47%) with a history of cancer. The median age was 73 years old. There were 29 Chinese (38.7%), 22 Indian (29.3%), 20 Malay (26.7%) and four other ethnicity patients. Some 83% and 73% of patients willing to accept strong and mild chemotherapy, respectively. Patients with cancer were more willing to accept strong and mild chemotherapy compared to the non-cancer group (88.6% vs 62.5%, P=0.005, 94% vs 80%, P=0.068). On sub-analysis, 71.4% and 42.9% of Chinese patients without a history of cancer were not willing to receive strong and mild chemotherapy, respectively. CONCLUSIONS The majority of elderly patients in UMMC were willing to receive chemotherapy if they had cancer. Experience with previous treatment had positive influence on the willingness to undergo chemotherapy.

Imatinib resistance and blast transformation of chronic myeloid leukemia associated with a novel tri-nucleotide insertion mutation of BCR-ABL kinase domain at position K294

A letter to the editor is presented which discusses the introduction of imatinib mesylate (IM) in the medical case of an 18-year old man with in-frame mutations and blast transformation of chronic myeloid leukemia (CML).