Host genetic variants of ABCB1 and IL15 influence treatment outcome in paediatric acute lymphoblastic leukaemia.

BACKGROUND: Host germline variations and their potential prognostic importance is an emerging area of interest in paediatric ALL. METHODS: We investigated the associations between 20 germline variations and various clinical end points in 463 children with ALL. RESULTS: After adjusting for known prognostic factors, variants in two genes were found to be independently associated with poorer EFS: ABCB1 T/T at either 2677 (rs2032582) or 3435 (rs1045642) position (P=0.003) and IL15 67276493G/G (rs17015014; P=0.022). These variants showed a strong additive effect affecting outcome (P<0.001), whereby patients with both risk genotypes had the worst EFS (P=0.001), even after adjusting for MRD levels at the end of remission induction. The adverse effect of ABCB1 T/T genotypes was most pronounced in patients with favourable cytogenetics (P=0.011) while the IL15 67276493G/G genotype mainly affected patients without common chromosomal abnormalities (P=0.022). In both cytogenetic subgroups, increasing number of such risk genotypes still predicted worsening outcome (P<0.001 and=0.009, respectively). CONCLUSION: These results point to the prognostic importance of host genetic variants, although the specific mechanisms remain unclarified. Inclusion of ABCB1 and IL15 variants may help improve risk assignment strategies in paediatric ALL.

Neuroblastoma: experience from National University Health System, Singapore (1987-2008).

INTRODUCTION: Neuroblastoma is the most common extracranial solid tumour in childhood. We report our experience at National University Health System (NUHS), Singapore. METHODS: We performed a retrospective chart review of 43 patients diagnosed with neuroblastoma, who were seen and treated at the Department of Paediatrics, NUHS from November 1987 to November 2008. RESULTS: The median age of the patients at diagnosis was 1.9 (range 0.1-20.2) years. The majority (70.1%) of primary tumours were of abdominal and/or adrenal origin. According to the International Neuroblastoma Staging System, six (14.0%) patients were in stages 1 and 2, 11 (25.6%) in stage 3, 19 (44.2%) in stage 4, and seven (16.2%) in stage 4s. Therapy for all patients included surgery and/or chemotherapy and/or radiation therapy. Patients with stage 4 disease also underwent autologous stem cell transplant. The median follow-up for the cohort was 2.5 (range 0.4-21.0) years. At the time of analysis, 29 (67.4%) patients were alive. The two- and five-year overall survival for the cohort was 65.0% (95% confidence interval [CI] 51.0%-80.0%) and 62.0% (95% CI 45.0%-79.0%), respectively. The five-year overall survival rates according to risk status were 100.0% for low-risk, 75.0% for intermediate risk and 28.2% for high-risk neuroblastoma. CONCLUSION: The prognosis for those with advanced stage neuroblastoma remains poor. A collaborative effort, with an emphasis on research in detecting biologic characteristics of aggressive disease and tailoring therapy, needs to be strengthened in order to further our understanding of this disease.

Dedicated cytogenetics factor is critical for improving karyotyping results for childhood leukaemias - experience in the National University Hospital, Singapore 1989-2006.

INTRODUCTION: Childhood leukaemia accounts for more than 40% of new childhood cancer cases. Karyotyping of cytogenetic abnormalities in such cases continues to provide critical prognostic information which allows the delivery of an appropriate intensity of treatment. Unfortunately, karyotyping of childhood leukaemia is difficult, laborious and often unsuccessful. Banding resolution tends to be poor unlike routine antenatal cytogenetics. The aim of the study is to highlight the benefit of dedicated cytogenetics in improving karyotyping results. MATERIALS AND METHODS: We analysed the impact of setting up a team of cytogeneticists in the National University Hospital (NUH) on the success of karyotyping, evaluating cytogenetic data collected from 1989 to 2006. From 1989 to 2006, 4789 cases have been processed. Among them, 369 newly diagnosed and relapsed childhood acute leukaemia cases [281 acute lymphoblastic leukaemia (ALL) and 88 acute myeloid leukaemia (AML)] have been diagnosed at NUH. A dedicated cytogenetics laboratory with clearly defined standard operating procedures and quality control was set up in 2002. It used the established recommendation of a complete analysis of at least 20 metaphases per analysis. RESULTS: Overall, the frequency of successful karyotyping was significantly higher (P = 0.002) at 90.7% (185/204) from 2002-2006 compared to 79.4% (131/165) from 1989-2001. For ALL cases, the success rate improved from 77.6% (97/125) in 1989 to 2001 to 89.1% (139/156) in the 2002 to 2006 cohort. For AML, the success rate also was significantly improved (P = 0.04) from 85% (34/40) to 95.8% (46/48). Significantly, this high rate of success is still maintained despite a yearly increase in volume. CONCLUSION: The establishment of a dedicated cytogenetics service leads to an improvement in results.

Obstetric admissions to the intensive therapy unit of a tertiary care institution.

INTRODUCTION: Between 0.1% and 0.9% of women develop pregnancy complications which require admission to an intensive therapy unit. The aim of this study was to review all obstetric admissions to the intensive therapy unit at the KK Women's and Children's Hospital from 1998 to 1999 with respect to indications for admission, interventions employed and clinical outcome. METHOD: The medical records of all obstetric patients admitted to the intensive therapy unit during the 2-year period were analysed retrospectively. Subjects were included if they were admitted during pregnancy up to 42 days postpartum. RESULTS: There were 31,725 deliveries in our hospital during the study period of which there were 239 admissions to the intensive therapy unit. Of these, 42% were Malays, 41% Chinese, 12% Indians and 5% other races. 65% stayed 1 day, 24% 2 days, 7% 3 days and 4% more than 3 days. The patients' ages ranged from 18 to 44 years. The indications for admission were hypertension (50%), haemorrhage (24%), respiratory insufficiency (10%), neurological problems (11%) and sepsis (3%). Intervention-wise, 43% of patients required vasoactive infusions, 35% had arterial line placement, 22% central venous pressure monitoring, 21% ventilatory support and 2% pulmonary artery catheter placement. The maternal mortality and stillbirth rates were 1.3% and 3.7% of intensive therapy unit admissions, respectively. CONCLUSION: The admission rate to the intensive therapy unit in our institution was 0.73% of all deliveries during the 2-year study period. Hypertensive disease and haemorrhage were the predominant admitting diagnoses.

Insulin-like growth factor binding proteins (IGFBPs) and IGFBP-related protein 1-levels in cerebrospinal fluid of children with acute lymphoblastic leukemia.

Abnormalities in insulin-like growth factor binding proteins (IGFBPs) have been reported in the cerebrospinal fluid (CSF) of children with acute leukemia. In the present study, we have further characterized the IGFBPs in whole CSF prospectively in 11 children with acute B-lineage lymphoblastic leukemia (ALL) undergoing chemotherapy. Western ligand blots Western immunoblots using a new anti-IGFBP-6 and a new IGFBP-rP1 (related protein-1 antibody and immunoassays (Diagnostic Systems Laboratories, Inc., Webster, TX) were used to characterize and measure IGFBP-6, IGFBP-2, IGFBP-3, and IGFBP-rP1 in children with ALL at diagnosis, and with treatment. Comparisons at baseline were made with 11 children with meningitis and 11 children with febrile convulsions (controls). The mean (+/- SE) CSF IGFBP-6 in ALL patients, 56 (+/- 7) ng/mL, was significantly lower than in meningitis, 97 (+/- 17) ng/mL; and in controls, 123 (+/- 24) ng/mL (P < 0.05, t test). In contrast, CSF IGFBP-3 was elevated in ALL patients, 29 (+/- 9) ng/mL; compared with meningitis, 11 (+/- 1) ng/mL; and controls, 10 (+/- 1) ng/mL (P < 0.05, t test); and IGFBP-2 did not differ among the three groups (47-59 ng/mL, P > 0.05). CSF IGFBP-6 remained very low in the patients with ALL, at 4 and 36 weeks of treatment; whereas IGFBP-3 decreased to control levels, and IGFBP-2 did not change significantly. At baseline, Western ligand blots and Western immunoblots identified a 25- to 28-kDa broad band as IGFBP-6 and a 30-kDa band as IGFBP-2 and showed that there was almost no intact IGFBP-3 in CSF. IGFBP-rP1 was also present in the CSF and was elevated in patients with ALL, compared with the 2 control groups. In conclusion, at diagnosis, IGFBP-rP1 and fragments of IGFBP-3 are elevated, and IGFBP-6 is significantly decreased, in the CSF of ALL children; and IGFBP-6 remained low, with treatment, up to 36 weeks. The role of the IGFBPs and IGFBP-rPs in central nervous system acute leukemia remain to be further elucidated.

Autologous bone marrow transplantation in a child with acute promyelocytic leukemia in second remission.

Acute myeloid leukemia (AML) comprises 15%-20% of childhood acute leukemia cases. The long-term disease free survival (DFS) in childhood AML is poor with standard chemotherapy alone. Early intensive chemotherapy is generally regarded to be necessary for achieving high complete remission (CR) rates. Recent experience has shown that incorporation of early intensification with high-dose melphalan conditioning and autologous bone marrow transplantation (BMT) during the first remission significantly improves long-term DFS in children with AML. In this article, we report the use of autologous BMT for treatment of a three-and-half year old child with acute promyelocytic leukemia (APL or M3) in second remission. The patient was conditioned with high-dose melphalan of 180 mg/kg prior to bone marrow reinfusion. A total of 4.0 x 10(7)/kg mononuclear cells and 1.07 x 10(5)/kg granulomonocytic colony forming units (CFU-GM) were infused. Haematopoietic stem cells were enriched by almost 20-fold after the separation and cryopreservation procedures. Haematological recovery was achieved four-and-a-half weeks post-BMT. She has remained in complete remission 18 months after transplantation. Our experience in this patient indicates that this procedure can be used in second remission and it may provide a better alternative for the management of childhood AML in Singapore.

An evaluation of minimal residual disease in childhood acute lymphoblastic leukaemia.

Evaluation of minimal residual disease (MRD) in acute lymphoblastic leukaemia (ALL) is important for disease prognostication and early relapse detection. In this study, the rearranged third complementarity-determining-region (CDR-III) of immunoglobulin heavy chain (IgH) was used as a surrogate tumour marker for MRD evaluation. DNA obtained from marrows at diagnosis was amplified by the polymerase chain reaction (PCR) using a pair of consensus primers. After 2 rounds of DNA amplification and polyacrylamide gel separation, the nucleotide sequences of 87.5% (21/24) consecutive children with B-lineage ALL were obtained by automated sequencing. There were between 1-4 rearrangements per patient. Although the J5 and J6 joining regions were preferentially used, the rearranged sequences were unique for all 25 sequences obtained. Oligoprobes to the DNJ region were constructed and quantitation in 7 patients showed a detection sensitivity of 1 leukaemic cell in 10(4) to 10(5) normal cells compared to 3 in 100 using conventional morphological criteria. Serial bone marrow showed progressive decrease in the quantity of leukaemic cells, and no leukaemic sequences were detected during cessation of therapy in 4/7 patients. One patient with detectable MRD, absconded treatment and eventually relapsed. These results are consistent with the need to eliminate the leukaemic clones below MRD detection levels before the end of therapy at 2 years. In conclusion, this study describes a novel, simplified and sensitive method of MRD detection in childhood leukaemia.