Andrzej Kołtan

Carrier frequency of mutation 657del5 in the NBS1 gene in a population of polish pediatric patients with sporadic lymphoid malignancies

Nijmegen breakage syndrome (NBS) is a human autosomal recessive disease characterized by genomic instability and enhanced cancer predisposition, in particular to lymphoma and leukemia. Recently, significantly higher frequencies of heterozygous carriers of the Slavic founder NBS1 mutation, 657del5, were found in Russian children with sporadic lymphoid malignancies, and in Polish adults with non‐Hodgkin lymphoma (NHL). In addition, the substitution 643C>T (R215W) has also been found in excess among children with acute lymphoblastic leukemia (ALL). In an attempt to asses the contribution of both mutations to the development of sporadic lymphoid malignancies, we analyzed DNA samples from a large group of Polish pediatric patients. The NBS1 mutation 657del5 on one allele was found in 3 of 270 patients with ALL and 2 of 212 children and adolescents with NHL; no carrier was found among 63 patients with Hodgkin lymphoma (HL). No carriers of the variant R215W were detected in any studied group. The relative frequency of the 657del5 mutation was calculated from a total of 6,984 controls matched by place of patient residence, of whom 42 were found to be carriers (frequency = 0.006). In the analyzed population with malignancies, an increased odds ratio for the occurrence of mutation 657del5 was found in comparison with the control Polish population (OR range 1.48–1.85, 95% confidence interval 1.18–2.65). This finding indicates that the frequency of the mutation carriers was indeed increased in patients with ALL and NHL (p < 0.05). Nonetheless, NBS1 gene heterozygosity is not a major risk factor for lymphoid malignancies in childhood and adolescence.

Beneficial and rapid effect of infliximab on the course of toxic epidermal necrolysis.

Sir, Toxic epidermal necrolysis (TEN) is a life-threatening dermatosis characterized by widespread detachment of the epidermis and mucosal erosions. Depending on the area of skin affected, case fatality rates vary from 20% to 60% (1, 2). The main causes of fatality are secondary infections caused by damage to the epidermis and multiorgan failure (2). Recent reports suggest that tumour necrosis factor alpha (TNF-α), released by activated keratinocytes and macrophages, plays a part in the pathogenesis of this disease (1, 3, 4). This implies that a selective TNF-α blockade could be a new and promising type of treatment. Infliximab is a chimeric monoclonal antibody with human and mouse components that binds specifically to both soluble and membrane-bound TNF-α.

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.

The application of conventional cytogenetics, FISH, and RT-PCR to detect genetic changes in 70 children with ALL

We investigated bone marrow cells of 70 acute lymphoblastic leukemia children by conventional cytogenetics (CC), fluorescence in situ hybridization (FISH), and reverse transcription polymerase chain reaction (RT-PCR) methods. CC and RT-PCR for fusion genes BCR/ABL, MLL/AF4, E2A/PBX1, TEL/AML1 were performed at diagnosis in each patient. FISH was performed to verify the presence of fusion genes and MLL rearrangements and to estimate the percentage of abnormal cells. Karyotypes were obtained in 59 (84%) of 70 cases. Thirty-five (59%) of 59 cases revealed chromosome aberrations. Hyperdiploidy >50 chromosomes was present in nine cases, hyperdiploidy 47–50 chromosomes in six, pseudodiploidy in 15, and hypodiploidy in five. BCR/ABL was present in two cases, PBX1/E2A in two, and TEL/AML1 in 14. MLL/AF4 was not found, but the rearrangements of MLL gene were present in five children. The addition of RT-PCR and FISH to CC was of the utmost importance. One of two Ph translocations and one of two t(1;19) were first revealed by RT-PCR. Moreover, FISH showed the percentage of TEL/AML1(+) cells that turned to be an important prognostic factor. The outcome was the best for the children with hyperdiploidy >50 chromosomes without structural changes. It was also good for those with TEL/AML1 present in ≥80% of cells without chromosome aberrations. The presence of pseudodiploidy correlated with poor outcome. The outcome for patients with t(9;22)–BCR/ABL or 11q23–MLL rearrangement was the worst in study group. The presence of BCR/ABL caused eight times increase of risk of death; MLL rearrangements caused 12 times increase.

Clinical features and treatment outcomes of peripheral T-cell lymphoma in children. A current data report from Polish Pediatric Leukemia/Lymphoma Study Group (PPLLSG)

PURPOSE Peripheral T-cell lymphomas (PTCL) are lymphoproliferative disorders derived from post-thymic cells, that occur extremely rarely in children. The optimal treatment of pediatric PTCL remains still unclear. PATIENTS AND METHODS Ten children with PTCL from 3 up to 18 years of age registered by the Polish Pediatric Leukemia/Lymphoma Study Group (PPLLSG) were retrospectively analyzed. All patients were treated with different regimens including protocols: for lymphoblastic lymphoma in 7 cases, for anaplastic large cell lymphoma in 1, CHOP in 1. Five of the 10 patients with PTCL were classified as stage II; 4 as stage III and 1 as stage IV due to extralymphatic organs (bone marrow) involvement. Four histological subtypes of PTCL were recognized: extranodal NK/T-cell lymphoma, nasal type (ENTNT), peripheral T-cell lymphoma not otherwise specified (PTCL-NOS), subcutaneous panniculitis-like T-cell lymphoma (SPL), Sezary syndrome (SS). After first-line therapy 9 patients initially achieved complete remission, 4 relapsed, 5 died. One patient achieved remission spontaneously. Three children (1 with stage IV and 2 in relapse) underwent high-dose chemotherapy with allogeneic bone marrow stem cell transplantation and all of them are alive and in CR. RESULTS The cumulative probability of 5-year overall survival (OS) for our whole group was 63.9% (95%CI: 35.2-88.2%) with a median follow-up time of 48.4 months (range 24-90+ months). The 5-year event free survival (EFS) was 81%. PTCLs are a heterogeneous and rare group of childhood NHLs. CONCLUSIONS According to our experience the standard chemotherapy for precursor lymphomas seems to be a beneficial treatment option for children with PTCL. Allogeneic stem cell transplantation may improve the outcome in selected patients.

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.

Differential chemosensitivity in a child with congenital relapsing acute lymphoblastic leukemia

Described is a case of a boy with congenital acute lymphoblastic leukemia (ALL) with pre-pre-B-ALL immunophenotype, presenting as diarrhea, organomegaly, hyperleucocytosis of 1434 G/L, and tumorlysis syndrome. The lymphoblasts showed low proliferative activity and high in vitro drug sensitivity measured by the MTT assay. An excellent response to therapy was observed, but relapse occurred 3 months later. On relapse, blasts showed extremely high drug resistance, high expression of P-glycoprotein, and high proliferative activity. The response to therapy was again positive, but a second relapse occurred in 1 month. The MTT assay indicated increasing drug resistance to all drugs. Cytogenetic analysis revealed deletion in 11q23 locus. This unfavorable case shows complex biology and differential drug resistance in congenital leukemia.

Imatinib in the treatment of chronic myeloid leukemia in children and adolescents is effective and well tolerated: Report of the Polish Pediatric Study Group for the Treatment of Leukemias and Lymphomas

BACKGROUND Chronic myeloid leukemia (CML) constitutes only 2-3% of all leukemias in pediatric patients. Philapelphia chromosome and BCR-ABL fusion are genetic hallmarks of CML, and their presence is crucial for targeted molecular therapy with tyrosine kinase inhibitors (TKIs), which replaced hematopoietic stem cell transplantation (HSCT) as a standard first-line therapy. The disease in pediatric population is rare, and despite molecular and clinical similarities to CML in adults, different approach is needed, due to the long lifetime expectancy and distinct developmental characteristics of affected children. OBJECTIVES The objective of this study is to evaluate treatment with imatinib in Polish pediatric patients with CML. MATERIAL AND METHODS We analyzed the results of treatment with imatinib in 57 pediatric patients (June 2006 - January 2016) from 14 Polish pediatric hematology and oncology centers. RESULTS In the study group, 40 patients continued imatinib (median follow-up: 23.4 months), while in 17 the treatment was terminated (median follow-up: 15.1 months) due to therapy failure. In the latter group, 13 patients underwent HSCT, while 4 switched to second-generation TKIs. The 5-year overall survival rate (OS) in the study group was 96%, and the 5-year event-free survival (EFS) was 81%. CONCLUSIONS Our results confirm that the introduction of TKI therapy has revolutionized the treatment of CML in the pediatric population by replacing the previous method of treatment with HSCT and allowing a high percentage of OS and EFS.

Outcome of acute lymphoblastic leukemia in children with down syndrome—Polish pediatric leukemia and lymphoma study group report

ABSTRACT Children with Down syndrome (DS) have a 20-fold increased risk of developing leukemia compared with the general population. The aim of the study was to analyze the outcome of patients diagnosed with Down syndrome and acute lymphoblastic leukemia (ALL) in Poland between the years 2003 and 2010. A total of 1848 children were diagnosed with ALL (810 females and 1038 males). Of those, 41 (2.2%) had DS. The children were classified into three risk groups: a standard-risk group—14 patients, an intermediate-risk group—24, a high-risk group—3. All patients were treated according to ALLIC 2002 protocol. The median observation time of all patients was 6.1 years, and in patients with DS 5.3 years. Five-year overall survival (OS) was the same in all patients (86% vs 86%, long-rank test, p = .9). The relapse-free survival (RFS) was calculated as 73% in patients with DS and 81% in patients without DS during a median observation time (long-rank test, p = .3). No statistically significant differences were found in the incidence of nonrelapse mortality between those two groups of patients (p = .72). The study was based on children with ALL and Down syndrome who were treated with an identical therapy schedule as ALL patients without DS, according to risk group. This fact can increase the value of the presented results.

Phenotype of NK Cells Determined on the Basis of Selected Immunological Parameters in Children Treated due to Acute Lymphoblastic Leukemia.

AbstractAcute lymphoblastic leukemia (ALL) is the most frequent pediatric malignancy. The chemotherapy for ALL is associated with a profound secondary immune deficiency.We evaluated the number and phenotype of natural killer (NK) cells at diagnosis, after the intensive chemotherapy and following the completion of the entire treatment for patients with ALL. The fraction, absolute number, and percentage of NK cells expressing interferon-&ggr; were determined in full blood samples. The fraction of NK cells expressing CD158a, CD158b, perforin, A, B, and K granzymes was examined in isolated NK cells.We have shown that patients assessed at ALL diagnosis showed significantly lower values of the fraction of NK cells and percentage of NK cells with the granzyme A expression. Additionally, the absolute number of NK cells, the expression of CD158a, CD158b, perforin, and granzyme A were significantly lower in patients who completed intensive chemotherapy. Also, there was a significantly higher fraction of NK cells expressing granzyme K in patients who completed the therapy.Abnormalities of NK cells were found at all stages of the treatment; however, the most pronounced changes were found at the end of intensive chemotherapy.