Genomic DNA-based measurable residual disease monitoring in pediatric acute myeloid leukemia: unselected consecutive cohort study.

Measurable residual disease (MRD) monitoring in childhood acute myeloid leukemia (AML) is used to assess response to treatment and for early detection of imminent relapse. In childhood AML, MRD is typically evaluated using flow cytometry, or by quantitative detection of leukemia-specific aberrations at the mRNA level. Both methods, however, have significant limitations. Recently, we demonstrated the feasibility of MRD monitoring in selected subgroups of AML at the genomic DNA (gDNA) level. To evaluate the potential of gDNA-based MRD monitoring across all AML subtypes, we conducted a comprehensive analysis involving 133 consecutively diagnosed children. Integrating next-generation sequencing into the diagnostic process, we identified (presumed) primary genetic aberrations suitable as MRD targets in 97% of patients. We developed patient-specific quantification assays and monitored MRD in 122 children. The gDNA-based MRD monitoring via quantification of primary aberrations with a sensitivity of at least 10-4 was possible in 86% of patients; via quantification with sensitivity of 5 × 10-4, of secondary aberrations, or at the mRNA level in an additional 8%. Importantly, gDNA-based MRD exhibited independent prognostic value at early time-points in patients stratified to intermediate-/high-risk treatment arms. Our study demonstrates the broad applicability, feasibility, and clinical significance of gDNA-based MRD monitoring in childhood AML.

The novel HLA-A*29:172 allele identified in a patient indicated for hematopoietic stem cell transplantation.

HLA-A*29:172 allele differs from HLA-A*29:01:01:01 by one missense single C/G nucleotide exchange in codon 77.

Severe linezolid-induced lactic acidosis in a child with acute lymphoblastic leukemia: A case report.

Linezolid is an antibiotic increasingly used for treatment of resistant Gram-positive infections, which blocks bacterial proteosythesis through direct inhibition of mitochondrial ribosomes. The most common adverse effects of linezolid include gastrointestinal symtoms, peripheral neuropathy, bone marrow depression and lactic acidosis. Here we present a rare case of a 9-year-old female, a survivor of acute lymphoblastic leukemia (ALL) and a hematopoietic stem cell transplant (HSCT), who developed life-threatening lactic acidosis with vomiting, impaired consciousness and Kussmaul breathing after 51 days of intravenous linezolid administration due to mycobacterial infection. She fully recovered after drug discontinuation and normalization of the plasma levels. We conclude that plasma lactate concentrations should be monitored closely during any linezolid treatment, particularly in patients with hepatic or renal dysfunction.

Chromosomal aberrations in childhood acute lymphoblastic leukemia: 15-year single center experience.

Genetic analysis of leukemic cells significantly impacts prognosis and treatment stratification in childhood acute lymphoblastic leukemia (ALL). Our retrospective single center study of 86 children with ALL enrolled into three consecutive treatment protocols (ALL-BFM 90, ALL-BFM 95 and ALL IC-BFM 2002) between 1991 and 2007 demonstrates the importance of conventional cytogenetics and fluorescence in situ hybridization (FISH). Cytogenetic and FISH examinations were performed successfully in 82/86 (95.3%) patients and chromosomal changes were detected in 78 of the 82 (95.1%) patients: in 69/73 patients with B-cell precursor (BCP)-ALL and in 9/9 patients with T-lineage ALL (T-ALL). The most frequent chromosomal changes in subgroups divided according to WHO classification independent of treatment protocol and leukemia subtype were hyperdiploidy in 36 patients (with ≥50 chromosomes in 23 patients, with 47-49 chromosomes 13 patients) followed by translocation t(12;21) with ETV6/RUNX1 fusion detected by FISH in 18 (22%) patients. Additional changes were detected in 16/18 (88.8%) ETV6/RUNX1-positive ALL patients with predominant deletion or rearrangement of untranslocated ETV6 allele. Unique aberrations were detected in 4 patients and dicentric chromosomes in 8 patients, one with T-ALL. These results demonstrate that cytogenetics and FISH successfully provided important prognostic information and revealed not only recurrent but also new and rare rearrangements requiring further investigation in terms of prognostic significance.

[The prospects for children with acute lymphoblastic leukemia of being cured has increased in the Czech Republic in the 21st century to 90% - outcome of the ALL-IC BFM 2002 trial]. / Sance na vylécení detí s akutní lymfoblastickou leukémií stoupla v Ceské republicev 21. století na 90 % - výsledky studie ALL IC-BFM 2002.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is the most frequent childhood malignancy. Treatment has been unified in the middle of 1980 in the Czech Republic. In 2002-2007 children and adolescents with acute lymphoblastic leukemia were treated in an international randomized trial ALL-IC BFM 2002 in the Czech Republic. 291 patients aged 1-18 years were enrolled; infants below 1 year entered a separate trial. METHODS AND RESULTS: Patients were stratified into three risk groups according to their age, initial leukocyte count, prednisone response, presence of fusion genes BCR/ABL or MLL/AF4, bone marrow D+15 and remission status D+33. The whole therapy took 24 months. Randomized late intensification compared standard BFM therapy with extended, usually more intensive experimental treatment. The median follow-up was 8.7 years. Complete remission was achieved in 97.9% patients, 1% died in remission. 11% of children relapsed, 1.7% with CNS involvement. Six children (2.1%) developed secondary malignancy. Event free survival (EFS) 8 years from diagnosis was 83.5%, overall survival (OS) 91.4%. EFS and OS of the risk groups were: standard risk: 89.4%; 98.1%; intermediate risk: 82.6%; 89.6%; high risk: 68.8%; 78.1%. Male sex and age above 10 years were adverse prognostic factors. CONCLUSIONS: In comparison with the previous trial ALL-BFM 95, significant improvement was achieved.

Combination of prednisolone and low dosed dexamethasone exhibits greater in vitro antileukemic activity than equiactive dose of prednisolone and overcomes prednisolone drug resistance in acute childhood lymphoblastic leukemia.

INTRODUCTION: Glucocorticoids, particularly prednisone/ prednisolone and dexamethasone, play a prominent role in the treatment of pediatric patients with acute lymphoblastic leukemia due to their ability to induce apoptosis in susceptible cells. Current therapeutic protocols use prednisone for both the prophase and the induction phase of the therapy because the greater antileukemic activity of dexamethasone is compromised by its high frequency of serious adverse reactions. AIM: To compare, for the first time, the in vitro antileukemic activity of prednisolone alone to that of a combination of prednisolone and dexamethasone using dexamethasone at a very low and presumably safe dosage (1/50 w/w). METHODS: Lymphoblasts were isolated from bone marrow and/or blood samples from children with newly diagnosed acute lymphoblastic leukemia. The cytotoxic activity of prednisolone, dexamethasone and the prednisolone/dexamethasone combination against isolated leukemia cells was analyzed using the MTT cytotoxicity assay. RESULTS: We observed differences in the in vitro antileukemic activity of prednisolone and dexamethasone in 21% of the tested patients. 3% of the children were prednisolone sensitive but dexamethasone resistant, while 18% were prednisolone resistant and dexamethasone sensitive. 32% were sensitive to both glucocorticoids and 18% were resistant to both. Cells from patients with good in vivo responses to prednisone monotherapy were more responsive to prednisolone in vitro than were cells from patients with poor prednisone responses (P<0.07). Importantly, we demonstrated that the use of even a minimal dose (1/50 w/w) of dexamethasone with prednisolone dramatically increases the in vitro anti-leukemic activity of prednisolone (P<0.0006). CONCLUSION: The high inter-individual variability of acute lymphoblastic leukemia responses to glucocorticoids suggest that either patients should be selected for prednisone or dexamethasone treatment on the basis of predictive biomarkers or that prednisone should be used directly in combination with a very low and safe dose of dexamethasone to potentiate its antileukemic activity. The latter option is likely to be cheaper and more efficient, and therefore warrants further clinical investigation to assess its efficacy and safety in treating childhood acute lymphoblastic leukemia.

Pediatric tumors of the parapharyngeal space. Three case reports and a literature review.

Three cases of pediatric primary parapharyngeal space tumors, namely a Burkitt's lymphoma, lipoblastoma and a ganglioneuroma are described here, along with a literature review. These disorders are very rare, accounting for less than 20% of all parapharyngeal neoplasms. In comparison to adults, there are differences in pathomorphologic spectrum of pediatric parapharyngeal tumors. The authors describe the prevalence of malignant tumors, mainly soft tissues sarcomas. The salivary gland tumors and paragangliomas which dominate in adult populations, are extremely rare in pediatric populations where the most common benign tumor to be encountered is that of neurogenic origin. It follows that these features modify the diagnostic and therapeutic approach.