Juvenile myelomonocytic leukaemia (JMML), previously known as juvenile chronic myeloid leukaemia (JCML) is a rare, myelodysplastic – myeloproliferative disease typically presenting in early childhood. This disorder is diffi cult to distinguish from other myeloproliferative syndrome such as chronic myeloid leukaemia (CML) because of the similarities in their clinical and bone marrow fi ndings. However, because of its unique biological characteristics such as absolute monocytosis with dysplasia, absence of Philadelphia chromosome or BCR-ABL fusion protein, hypergammaglobulinaemia and raised fetal haemoglobin level, this disorder does not satisfy the criteria for inclusion in the CML or chronic myelomonocytic leukaemia (CMML) group, as seen in adult patients. We describe a series of three patients with JMML, who had almost similar clinical and laboratory fi ndings, and discuss the diffi culty in the classifi cation and treatment of the disease.

MicroRNAs (miRNAs) are mostly located at cancer-associated genomic regions or in fragile sites, suggesting their important role in the pathogenesis of human cancers. Multiple myeloma (MM) is a cancer of plasma cells, the third most common cancer of the blood after lymphoma and leukaemia. There are several published reports on miRNAs in MM, however most used bone marrow rather than peripheral blood samples. The aim of this study is to characterise miRNA expression in normal and MM patients using peripheral blood samples as it is less invasive and is readily available from patients. Blood samples from 35 MM patients were analysed using the microarray method. We identified up-regulation of 36 miRNAs (57%) and down-regulation of 27 miRNAs (43%). We also identified the CCND2, HMGA2 and IGF1R genes were among the highly predictive target genes (P(CT) > 0.80) for most of the deregulated miRNAs. These genes are known to play important roles in MM as well as other cancers. Five miRNAs (let-7c, miR-16, miR- 449, miR-181a and miR-181b) were found to exhibit similar expression patterns (p < 0.05) in peripheral blood when compared to data obtained by using bone marrow aspirates from MM patients in other studies. In conclusion, our study has demonstrated that miRNAs are also present and differentially expressed in the peripheral blood of MM patients compared to controls and may potentially serve as candidate tumour biomarkers in MM. In particular, let-7c and miR-16 have been shown to be significantly expressed in the bone marrow.

Residual disease in patients with acute leukaemia indicates unfavorable prognosis. The evaluation of remission using flow cytometry allows a better estimation of minimal residual disease (MRD) after induction chemotherapy in childhood acute lymphoblastic leukaemia (ALL) cases. Patients in morphological marrow remission with presence of blast cells of less than 5%, may still have up to 1010 leukaemic cells. However with flow cytometric analysis, lower levels of the residual leukaemic cells (1 in 104 cells) can be detected and it can be used as a tool to predict relapse. This study compared the presenting clinical and haematological features of children with ALL and their residual disease status determined by flow cytometry. Analysis of their MRD status following remission-induction chemotherapy were done at day-28, week-12 and week-20. The cases were also followed up to five years, to determine their survival status. Their residual disease status by flow cytometric immunophenotyping was also compared with their bone marrow findings morphologically. Thirty-eight cases of precursor B-ALL in pediatric patients from UKM Medical Centre (UKMMC) were analyzed. There was no significant correlation between demographic, clinical and haematological features with MRD status at day-28. However, there was a significant correlation between MRD status by flow cytometry and by morphological marrow examination at week-12. Three cases showed persistent MRD findings until week-20 where two of the cases relapsed and died subsequently. Twenty four patients were still alive after five years of follow up.