Katarzyna Derwich

Additional genetic risk factor for death in children with acute lymphoblastic leukemia: A common polymorphism of the MTHFR gene

The presence of metabolically important genetic polymorphisms may affect treatment efficacy in patients with malignancies. The objective of this prospective multicenter study was to evaluate the role of selected polymorphisms of genes associated with metabolism of chemotherapeutic drugs as prognostic markers in children with acute lymphoblastic leukemia.

Vascular endothelial growth factor [VEGF]-C - a potent risk factor in children diagnosed with stadium 4 neuroblastoma

To evaluate the immunohistochemical expression of VEGF-C, CD34 and VEGFR-2 in cancer tissue of children diagnosed with stadium 4 neuroblastoma (NB) and correlate their presence with the survival rate of children diagnosed with that stage of the disease. Eighteen children assigned to stadium 4 composed the study group. Fourteen patients (allocated to stadium 3) formed a control group. VEGF-C, CD34 and VEGFR-2 expressions were evaluated by immunohistochemical assay. Consecutive slides incubated with anti-CD34 and anti-VEGFR-2 antibodies revealed that the two markers were colocalized within endothelial layer of the blood vessels. On the other hand, VEGF-C was expressed exclusively in tumour cells. As demonstrated by Fishers exact test, the risk of NB treatment failure (progression or relapse) as well as tumour related death, when all the patients were considered, was found to be significant in VEGF-C positive patients. VEGF-C expression in NB constitutes a potent risk factor and may direct future anti-angiogenic treatment strategy. The proximity of VEGF-C and CD34/VEGFR-2 of NB could be the equivalent of a potentially interesting VEGF-C fashion involving a tumour cell invasion into the blood vessels in an early phase of metastases promoting.

Methods of minimal residual disease (MRD) detection in childhood haematological malignancies

The appropriate management of haematological disorders must rely on a precise and long-term monitoring of the patient’s response to chemotherapy and radiotherapy. Clinical data are not sufficient and that is why in the last decade it became the most important to improve the knowledge of haematological diseases on the basis of molecular techniques and molecular markers. The presence of residual malignant cells among normal cells is termed minimal residual disease (MRD). Nowadays a great progress has been made in the treatment of malignant diseases and in the development of reliable molecular techniques, which are characterised by high sensitivity (10−3–10−6) and ability to distinguish between normal and malignant cells at diagnosis and during follow-up. Especially, MRD data based on quantitative analysis (RQ-PCR, RT-RQ-PCR) appear to be crucial for appropriate evaluation of treatment response in many haematological malignancies. Implementation of standardized approaches for MRD assessment into routine molecular diagnostics available in all oncohaematological centres should be regarded nowadays a crucial point in further MRD study development.

Biallelic loss of CDKN2A is associated with poor response to treatment in pediatric acute lymphoblastic leukemia

Abstract The inactivation of tumor suppressor genes located within 9p21 locus (CDKN2A, CDKN2B) occurs in up to 30% of children with B-cell precursor acute lymphoblastic leukemia (BCP-ALL), but its independent prognostic significance remains controversial. In order to investigate the prognostic impact of deletions and promoter methylation within 9p21, 641 children with newly diagnosed BCP-ALL using methylation specific multiplex ligation-dependent probe amplification (MS-MLPA) were investigated. A total of 169 (26.4%) microdeletions in 9p21 were detected, of which 71 were homozygous. Patients with CDKN2A homozygous deletions were older at diagnosis (p < .001), more frequently steroid resistant (p = .049), had higher WBC count (p < .001), higher MRD at Day 15 (p = .013) and lower relapse-free survival [p = .028, hazard ratio: 2.28 (95% confidence interval: 1.09–4.76)] than patients without these alterations. CDKN2A homozygous deletions coexisted with IKZF1 and PAX5 deletions (p < .001). In conclusion, CDKN2A homozygous deletions, but not promoter methylation, are associated with poor response to treatment and increased relapse risk of pediatric BCP-ALL.

Implementation of the standard strategy for identification of Ig/TCR targets for minimal residual disease diagnostics in B-cell precursor ALL pediatric patients: Polish experience

Introduction:Minimal residual disease (MRD), detected based on immunoglobulin and T-cell receptor (Ig/TCR) gene rearrangements as markers of residual leukemic cells, is currently the most reliable prognostic factor in acute lymphoblastic leukemia (ALL). A feasibility study is presented of the standard strategy for the identification of Ig/TCR targets for MRD diagnostics in Polish ALL patients by identifying Ig/TCR gene rearrangement pattern using standard primer sets and protocols.Materials and Methods:The PCR-heteroduplex approach based on BIOMED-1 and BIOMED-2 protocols (recommended as the European standard) was used to detect IGH, IGK-Kde, TCRD, TCRG, and TCRB rearrangements in 58 Polish B-cell precursor ALL patients. Sequencing and homology analysis between the obtained and germline Ig/TCR sequences enabled identification of the rearrangements. The U-Gauss test was used for statistical analysis of the Ig/TCR rearrangement pattern in Polish patients compared with relevant data on other nationalities.Results:The following pattern was identified: IGH: 83% (VH-JH: 74%, DH-JH: 9%), IGK-Kde: 41%, TCRD: 78% (incomplete TCRD: 55%, Vδ2-Dδ3: 45%, Dδ2-Dδ3: 21%, Vδ2-Jα: 35%), TCRG: 50%, and TCRB: 13%. Considerable convergence of the Ig/TCR pattern in Polish patients and those of other nationalities (mainly West Europeans) was demonstrated. Statistically relevant differences were only found between the incidence of DH-JH in Polish (9%) and Dutch patients (24%; p<0.05) and Polish and Italian patients (19%; p<0.05), VH-JH in Polish (74%) and Chilean patients (100%; p<0.05), and TCRG in Polish (50%) and Brazilian patients (69%; p<0.05).Conclusions:The convergence of Ig/TCR patterns in Polish and European patients indicates that the strategy for Ig/TCR target identification based on standard primers and protocols might be directly used for the construction of Polish standards and recommendations for MRD diagnostics.

Infant acute bilineal leukemia

Most cases of acute leukemia can be assigned to the myeloid, B or T lineage. There are rare cases of acute leukemia, which cannot be clearly classified, because either blasts express antigens of more than one lineage (acute biphenotypic leukemias) or distinct blast populations of two lineages co-exist (acute bilineal leukemias, aBLL). We present a 10-month-old infant with de novo aBLL, characterized by blasts of monocytic and B-cell precursor lineages. All leukemic cells harbored identical complex MLL gene rearrangement. Despite poor initial response, both to acute lymphoblastic leukemia (ALL) induction treatment and acute myeloid leukemia induction blocks, the child reached complete clinical remission with minimal residual disease negative status and was transplanted. Unfortunately, 16 months from HSCT the patient experienced BM relapse with all blasts characterized by pro-B-ALL immunophenotype. This case report illustrates that aBLL is a very aggressive type of acute leukemia that should be individually treated and monitored, particularly in children less than 1 year of age.

Ph‐negative isolated myeloid sarcoma with NPM1 gene mutation in adolescent with Ph‐positive chronic myeloid leukemia in remission after treatment with allogeneic bone marrow transplantation and imatinib mesylate

Few patients in remission of Ph‐positive chronic myelogenous leukemia (CML) develop Ph‐negative MDS/AML, usually with clonal cytogenetic abnormalities. Isolated Ph‐negative myeloid sarcoma (MS) is presented here as a form of such disorder, different from Ph‐positive MS establishing CML relapse in blastic phase. We describe 11‐year‐old male who developed Ph‐negative isolated MS with NPM1 mutation, remaining in complete molecular remission of Ph‐positive chronic myeloid leukemia treated with allo‐HSCT in first chronic phase and with imatinib and donor lymphocyte infusion in molecular relapse. The possible mechanisms of the tumor formation are reviewed with stress on importance of comprehensive molecular/cytogenetic evaluations. Pediatr Blood Cancer 2015;62:1070–1071.

Anti-leukemic treatment-induced neurotoxicity in long-term survivors of childhood acute lymphoblastic leukemia: impact of reduced central nervous system radiotherapy and intermediate- to high-dose methotrexate

Abstract The aim of the study was to evaluate the long-term neurodevelopmental consequences of currently applied acute lymphoblastic leukemia (ALL) therapy containing chemotherapy alone or combined with 12 Gy radiotherapy. Seventy-nine children aged 6.3–21.7 years diagnosed with ALL and treated according to ALL IC-BFM 2002 have been studied. The control group consisted of 23 children newly diagnosed with ALL. We assessed subcortical gray matter volume using automatic MRI segmentation and cognitive performance to identify differences between three therapeutic schemes and patients prior to treatment. Irradiated patients had smaller selected subcortical volumes than those treated with chemotherapy alone and than the controls, while the chemotherapy group had similar volumes as the control one. In neurocognitive assessment, irradiated children performed worse in major domains than the control group. There were no significant results for patients after high dose chemotherapy without radiotherapy. There was a significant relationship between full scale IQ together with verbal learning and volumes of hippocampus, amygdala, and pallidum. In all children treated for ALL, both decreased volume of selected subcortical structures and cognitive impairment were observed, especially in children who were irradiated.

Myeloid sarcoma in children – diagnostic and therapeutic difficulties

Myeloid sarcoma (MS) is a malignant extramedullary tumour, which consists of immature cells of myeloid origin. It may occur de novo, concurrently or precede the diagnosis of acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) or chronic myeloid leukemia (CML). MS can also be a manifestation of the relapse of the disease. The more frequent sites of involvement are the skin, orbit, bone, periosteum, lymph nodes, gastrointestinal tract, soft tissue, central nervous system and testis. Because of its different localization and symptoms, and the lack of diagnostics algorithm, myeloid sarcoma is a real diagnostic challenge, in particular in patients without initial bone marrow involvement. The correct diagnosis of MS is important for adequate therapy, which is often delayed because of a high misdiagnosis rate. In the paper, the role of immunohistochemistry, cytogenetic and molecular genetic analyses is emphasized as well as the breadth of unclear aspects of this disorder in children.

Association of germline genetic variants in RFC, IL15 and VDR genes with minimal residual disease in pediatric B-cell precursor ALL

Minimal residual disease (MRD) enables reliable assessment of risk in acute lymphoblastic leukemia (ALL). However, little is known on association between MRD status and germline genetic variation. We examined 159 Caucasian (Slavic) patients with pediatric ALL, treated according to ALL-IC-BFM 2002/2009 protocols, in search for association between 23 germline polymorphisms and MRD status at day 15, day 33 and week 12, with adjustment for MRD-associated clinical covariates. Three variants were significantly associated with MRD: rs1544410 in VDR (MRD-day15); rs1051266 in RFC (MRD-day33, MRD-week12), independently and in an additive effect with rs10519613 in IL15 (MRD-day33). The risk alleles for MRD-positivity were: A allele of VDR (OR = 2.37, 95%CI = 1.07–5.21, P = 0.03, MRD-day15); A of RFC (OR = 1.93, 95%CI = 1.05–3.52, P = 0.03, MRD-day33 and MRD-week12, P < 0.01); A of IL15 (OR = 2.30, 95%CI = 1.02–5.18, P = 0.04, MRD-day33). The risk for MRD-day33-positive status was higher in patients with risk alleles in both RFC and IL15 loci than in patients with risk alleles in one locus or no risk alleles: 2 vs. 1 (OR = 3.94, 95% CI = 1.28–12.11, P = 0.024), 2 vs. 0 (OR = 6.75, 95% CI = 1.61–28.39, P = 0.012). Germline variation in genes related to pharmacokinetics/pharmacodynamics of anti-leukemic drugs and to anti-tumor immunity of the host is associated with MRD status and might help improve risk assessment in ALL.