Extended induction chemotherapy does not improve the outcome for high-risk neuroblastoma patients: results of the randomized open-label GPOH trial NB2004-HR.

BACKGROUND: Long-term survival of high-risk neuroblastoma patients is still below 50% despite intensive multimodal treatment. This trial aimed to address whether the addition of two topotecan-containing chemotherapy courses compared to standard induction therapy improves event-free survival (EFS) of these patients. PATIENTS AND METHODS: An open-label, multicenter, prospective randomized controlled trial was carried out at 58 hospitals in Germany and Switzerland. Patients aged 1-21 years with stage 4 neuroblastoma and patients aged 6 months to 21 years with MYCN-amplified tumors were eligible. The primary endpoint was EFS. Patients were randomly assigned to standard induction therapy with six chemotherapy courses or to experimental induction chemotherapy starting with two additional courses of topotecan, cyclophosphamide, and etoposide followed by standard induction chemotherapy (eight courses in total). After induction chemotherapy, all patients received high-dose chemotherapy with autologous hematopoietic stem cell rescue and isotretinoin for consolidation. Radiotherapy was applied to patients with active tumors at the end of induction chemotherapy. RESULTS: Of 536 patients enrolled in the trial, 422 were randomly assigned to the control arm (n = 211) and the experimental arm (n = 211); the median follow-up time was 3.32 years (interquartile range 1.65-5.92). At data lock, the 3-year EFS of experimental and control patients was 34% and 32% [95% confidence Interval (CI) 28% to 40% and 26% to 38%; P = 0.258], respectively. Similarly, the 3-year overall survival of the patients did not differ [54% and 48% (95% CI 46% to 62% and 40% to 56%), respectively; P = 0.558]. The response to induction chemotherapy was not different between the arms. The median number of non-fatal toxicities per patient was higher in the experimental group while the median number of toxicities per chemotherapy course was not different. CONCLUSION: While the burden for the patients was increased by prolonging the induction chemotherapy and the toxicity, the addition of two topotecan-containing chemotherapy courses did not improve the EFS of high-risk neuroblastoma patients and thus cannot be recommended. CLINICAL TRIALS. GOV NUMBER: NCT number 03042429.

Higher fibrinogen concentrations for reduction of transfusion requirements during major paediatric surgery: A prospective randomised controlled trial.

BACKGROUND: Hypofibrinogenaemia is one of the main reasons for development of perioperative coagulopathy during major paediatric surgery. The aim of this study was to assess whether prophylactic maintenance of higher fibrinogen concentrations through administration of fibrinogen concentrate would decrease the volume of transfused red blood cell (RBCs). METHODS: In this prospective, randomised, clinical trial, patients aged 6 months to 17 yr undergoing craniosynostosis and scoliosis surgery received fibrinogen concentrate (30 mg kg(-1)) at two predefined intraoperative fibrinogen concentrations [ROTEM(®) FIBTEM maximum clot firmness (MCF) of <8 mm (conventional) or <13 mm (early substitution)]. Total volume of transfused RBCs was recorded over 24 h after start of surgery. RESULTS: Thirty children who underwent craniosynostosis surgery and 19 children who underwent scoliosis surgery were treated per protocol. During craniosynostosis surgery, children in the early substitution group received significantly less RBCs (median, 28 ml kg(-1); IQR, 21 to 50 ml kg(-1)) compared with the conventional fibrinogen trigger of <8 mm (median, 56 ml kg(-1); IQR, 28 to 62 ml kg(-1)) (P=0.03). Calculated blood loss as per cent of estimated total blood volume decreased from a median of 160% (IQR, 110-190%) to a median of 90% (IQR, 78-110%) (P=0.017). No significant changes were observed in the scoliosis surgery population. No bleeding events requiring surgical intervention, postoperative transfusions of RBCs, or treatment-related adverse events were observed. CONCLUSIONS: Intraoperative administration of fibrinogen concentrate using a FIBTEM MCF trigger level of <13 mm can be successfully used to significantly decrease bleeding, and transfusion requirements in the setting of craniosynostosis surgery, but not scoliosis. CLINICAL TRIAL REGISTRY NUMBER: ClinicalTrials.gov NCT01487837.

[Age-related characteristics of the efficacy of different glucocorticosteroids in the therapy of acute lymphoblastic leukemia].

AIM: To determine predictors for decision-making on a differential approach to choosing glucocorticosteroids (GCS) for children and adolescents with acute lymphoblastic leukemia (ALL). SUBJECTS AND METHODS: The analysis covered 1064 primary patients aged to 1 to 18 years with ALL who had been registered at the clinics of Russia and Belorussia in April 2002 to November 2006. Before induction therapy, the patients were randomized into a dexamethasone (DEXA) 6 mg/m2 group (n=539) and a methylprednisolone (MePRED) 60 mg/m2 one (n=525). RESULTS: The entire group showed no statistically significant differences in survival rates between the patients receiving DEXA or MePRED. However, an analysis of age groups revealed the benefits of DEXA in children younger than 14 years (the event-free survival (EFS) was 76±2 and 71±2%, respectively (p=0.048); the overall survival (OS) was 81±2 and 77±2%, respectively (p=0.046); therapy-induced mortality was 6.4% (DEXA) andl 1.1% (MePRED) (p=0.01 4); the rate of isolated extramedullary relapses was 1.5% (DEXA) and 4.4% (MePRED) (p=0.009). At the same time, EFS and OS in 14-to-18-year-old adolescents were statistically significantly higher than in those who used MePRED (EFS, 65±6 and 52±6%, respectively (p=0.087); OS, 72±6 and 61±6%, respectively; (p=0.l 7). CONCLUSION: The findings suggest that it is possible that the choice of a GCS for ALL therapy must be also based on a patient's age. There is a need for further studies of this matter in prospective randomized multicenter trials in children and adolescents.

Musculoskeletal pain: a new algorithm for differential diagnosis of a cardinal symptom in pediatrics.

Musculoskeletal pain (MSP) is a common childhood complaint associated with multiple differential diagnoses, including cancer. Considering the expanding spectrum of diagnostics, evaluat-ing a young patient with MSP is a challenge today, particularly for non-specialists in a primary care setting. Since childhood cancer is rare and most cardinal symptoms mimic rather non-serious diseases, misdiagnosis is not uncommon, but of significant prognostic relevance. To build the appropriate bridge between primary and secon-dary care for a child presenting with MSP, thereby preventing treatment delay and longterm sequelae, initial evaluation should follow a comprehensive, multidisciplinary, systematic and stepwise approach, which unites the patient's individual anamnestic, psychosocial, and clinical charac-teristics. After a systematic review of the literature, we generated multidisciplinarily quality-assured recommendations for efficient, rational and cost-effective primary care assessment of pediatric MSP. The algorithm promotes the identification and structured interpretation of the patient's individual clinical clues. It should serve the primary care physician to recognize when further intervention, rather than reassurance and follow-up, is needed using the minimum amount of testing to make an appropriate, prompt diagnosis in the clinical situation "child presenting with MSP". A German version of this algorithm has been published in the Guideline-Portal of The Association of the Scientific Medical Societies ("Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften", AWMF) in November 2013.

Effective childhood cancer treatment: the impact of large scale clinical trials in Germany and Austria.

In Germany and Austria, more than 90% of pediatric cancer patients are enrolled into nationwide disease-specific first-line clinical trials or interim registries. Essential components are a pediatric cancer registry and centralized reference laboratories, imaging review, and tumor board assistance. The five-year overall survival rate in countries where such infrastructures are established has improved from <20% before 1950 to >80% since 1995. Today, treatment intensity is tailored to the individual patient's risk to provide the highest chances of survival while minimizing deleterious late effects. Multicenter clinical trials are internationalized and serve as platforms for further improvements by novel drugs and biologicals.

ALL-REZ BFM--the consecutive trials for children with relapsed acute lymphoblastic leukemia.

The BFM studies for relapsed childhood acute lymphoblastic leukemia (ALL) were started in 1983, at a time when cure rates for ALL were still lower and the number of children with ALL relapse equaled about the number of children with newly diagnosed neuroblastoma. Today, relapses have become relatively rare events in ALL although, because of the frequency of ALL, they are still a significant cause of death in children and adolescents. With currently used treatment modalities, cure rates of about 50% after relapse can be achieved, and, together with the improved results of front-line therapy, the survival rate of childhood ALL is now about 90%. Most children with extramedullary and late bone marrow (BM) relapses achieve a second CR; remission rates in patients with high-risk features, however, remain still unsatisfactory. With improved techniques allogeneic hematopoietic stem cell transplant (HSCT) has become a relatively safe treatment but is not necessary for all patients as postremission therapy. HSCT is not required in children with isolated extramedullary and late BM relapses with rapid response to induction therapy measured by molecular techniques (minimal residual disease, MRD) but absolutely indicated in patients with early BM relapses and systemic relapses of T-cell ALL. For patients with insufficient response innovative therapies such as small molecules or targeted immunological or pharmacological approaches are urgently required. Efforts have to be made, therefore, in order to detect potential biological or molecular targets, which can be used for individualized, more effective and hopefully less toxic therapies in the future.

Key treatment questions in childhood acute lymphoblastic leukemia: results in 5 consecutive trials performed by the ALL-BFM study group from 1981 to 2000.

Between 1981 and 2000, 6 609 children (<18 years of age) were treated in 5 consecutive trials of the Berlin-Frankfurt-Münster (BFM) study group for childhood acute lymphoblastic leukemia (ALL). Patients were treated in up to 82 centers in Germany, Austria, and Switzerland. Probability of 10-year event-free survival (survival) improved from 65% (77%) in study ALL-BFM 81-78% (85%) in ALL-BFM 95. In parallel to relapse reduction, major efforts focused on reducing acute and late toxicity through advanced risk adaptation of treatment. The major findings derived from these ALL-BFM trials were as follows: 1) preventive cranial radiotherapy could be safely reduced to 12 Gy in T-ALL and high-risk ALL patients and eliminated in non-high-risk non-T-ALL patients, if it was replaced by high-dose and intrathecal methotrexate; 2) omission of delayed reintensification severely impaired outcome of low-risk patients; 3) 6 months less maintenance therapy caused an increase in systemic relapses; 4) slow response to an initial 7-day prednisone window was identified as adverse prognostic factor; 5) condensed induction therapy resulted in a significant improvement of outcome; 6) the daunorubicin dose in induction could be safely reduced in low-risk patients; 7) intensification of consolidation/reintensification treatment led to considerable improvement of outcome in high-risk patients.

Low inhibin B levels alone are not a reliable marker of dysfunctional spermatogenesis in childhood cancer survivors.

Hormone and semen analyses were carried out to examine the diagnostic value of hormones and hormone combinations as markers of spermatogenesis in male patients who had received oncological treatment in childhood. Hormone analyses from 73 participants and spermiograms from 42 participants were evaluated. Spearman's correlation coefficients and measures of diagnostic accuracy were calculated for the hormone and semen analysis values. Inhibin B levels of <80 ml/ml, follicle-stimulating hormone (FSH) levels of >10 IU l(-1) and a combination of the two parameters showed positive predictive values for azoospermia of 0.423, 0.6154 and 0.6667 respectively. While 32% of the 73 participants showed a combination of abnormal inhibin B and FSH values, which strongly indicates impaired spermatogenesis, 31% of the 42 spermiogram results revealed azoospermia. The hormone and semen analyses showed that approximately one-third of the participants had fertility impairment. Inhibin B alone thus does not reflect spermatogenesis as well as inhibin B in combination with FSH in patients who have undergone cancer treatment in childhood. Both parameters should therefore be evaluated in paediatric cancer follow-up programmes to allow better identification of treatment regimens that cause persistent azoospermia in male childhood cancer survivors.

Evaluation of interim PET response criteria in paediatric Hodgkin's lymphoma--results for dedicated assessment criteria in a blinded dual-centre read.

BACKGROUND: The aim of this study was to evaluate the use and reliability of the new positron emission tomography (PET)-based response criteria for interim positron emission tomography (iPET) in patients with paediatric Hodgkin's lymphoma (pHL). Particular emphasis was put on interobserver variability and on identification of a visual cut-off defining patients with very low risk for relapse. PATIENTS AND METHODS: The iPET scans of 39 pHL patients were evaluated in two independent centres by two PET-experienced specialists in nuclear medicine (blinded read, centre consensus) each. The iPET scans were interpreted using a 5-point scale and were compared with the outcome. Cohen's kappa-test (κ) was used to analyse the interobserver agreement. RESULTS: Concordant ratings were assessed in 19 patients with iPET-negative findings, in 11 patients with iPET-positive findings and in 2 patients with inconclusive ratings. A 'substantial agreement' between attended centres was achieved (κ = 0.748). All patients suffering relapse were concordantly identified, taking mediastinal blood pool structures (MBPS) as visual cut-off between PET-positive and PET-negative findings, respectively. All pHL patients with uptake lower than or equal to MBPS remained in complete remission. CONCLUSION(S): The iPET interpretation assured low interobserver variability. High sensitivity for identification of pHL patients suffering relapse is achieved if [18F]-fluorodeoxyglucose uptake above the MBPS value is rated as a PET-positive finding.

High reliability of scrotal ultrasonography in the management of childhood primary testicular neoplasms.

BACKGROUND: The role for testis-sparing surgery in the treatment of primary intratesticular lesions in childhood is growing. The reliability of scrotal ultrasonograpy (US) in the management of these lesions is still controversial. PATIENTS: Between 1991 and 2007, 383 children and adolescents presented with testicular abnormalities. Ultrasound results and records of patients with primary testicular neoplasms were analyzed. RESULTS: 12 of 383 patients (3.1%) had a histologically proven primary intratesticular neoplasm. Scrotal US was highly sensitive for the detection of these lesions. Patients' mean age at initial US was 6 years (9 prepubertal, 3 juvenile patients). The most frequent symptom was a painless unilateral scrotal mass (75%). Tumor markers or testosterone were elevated in 6/12 boys. Histology was intratesticular germ cell in 7, sexcord stromal tumor in 4 and capillary hemangioma in 1 patient. US correctly distinguished between benign and malignant lesions in all cases. When combined with clinical symptoms, US predicted 75% of histologies. After including hormone and tumor marker levels, a correct preoperative diagnosis was made for all boys with germ cell, and for 75% of boys with sexcord stromal tumor. CONCLUSION: Scrotal US is highly sensitive for the detection of childhood primary intratesticular tumors and, when combined with clinical data, highly reliable for differential diagnosis. It may help clinicians to decide when to opt for testis-sparing surgery.

A graph neural network framework for causal inference in brain networks.

A central question in neuroscience is how self-organizing dynamic interactions in the brain emerge on their relatively static structural backbone. Due to the complexity of spatial and temporal dependencies between different brain areas, fully comprehending the interplay between structure and function is still challenging and an area of intense research. In this paper we present a graph neural network (GNN) framework, to describe functional interactions based on the structural anatomical layout. A GNN allows us to process graph-structured spatio-temporal signals, providing a possibility to combine structural information derived from diffusion tensor imaging (DTI) with temporal neural activity profiles, like that observed in functional magnetic resonance imaging (fMRI). Moreover, dynamic interactions between different brain regions discovered by this data-driven approach can provide a multi-modal measure of causal connectivity strength. We assess the proposed model's accuracy by evaluating its capabilities to replicate empirically observed neural activation profiles, and compare the performance to those of a vector auto regression (VAR), like that typically used in Granger causality. We show that GNNs are able to capture long-term dependencies in data and also computationally scale up to the analysis of large-scale networks. Finally we confirm that features learned by a GNN can generalize across MRI scanner types and acquisition protocols, by demonstrating that the performance on small datasets can be improved by pre-training the GNN on data from an earlier study. We conclude that the proposed multi-modal GNN framework can provide a novel perspective on the structure-function relationship in the brain. Accordingly this approach appears to be promising for the characterization of the information flow in brain networks.

[Procedure guidelines for whole-body 18F-FDG PET and PET/CT in children with malignant diseases]. / Empfehlungen zur Durchführung der Ganzkörper-18F-FDG-PET und -PET/CT bei Kindern mit onkologischen Erkrankungen. Anpassung der EANM-Guideline an aktuelle Gegebenheiten in Deutschland.

The purpose of these guidelines is to offer the nuclear medicine and the appropriate interdisciplinary team a framework for performing and reporting positron emission tomography (PET) and the combination with computed tomography (PET/CT) in children with malignant diseases mainly using the radiopharmaceutical 18F-fluorodeoxy-glucose (FDG). These guidelines are based on the recent guidelines of the Paediatric Committee of the European Association of Nuclear Medicine (EANM) (57) and have been translated and adapted to the current conditions in Germany. The adaptation of CT-parameters using PET/CT in children is covered in a more detailed way than in the EANM guideline taking into account that in Germany already a good portion of PET examinations is performed using an integrated PET/CT-scanner. Furthermore, a CT-scan without adoption of the CT acquisition parameters would result in a not tolerably high radiation exposition of the child. There are excellent guidelines for FDG PET and PET/CT in oncology published by the German Society of Nuclear Medicine (Deutsche Gesellschaft für Nuklearmedizin, DGN) (42) and EANM (4). These guidelines aim at providing additional information on issues particularly relevant to PET and PET/CT imaging in children. These guidelines should be taken in the context of local and national current standards of quality and rules.

Hormone and Sperm Analyses after Chemo- and Radiotherapy in Childhood and Adolescence.

BACKGROUND: Since prevalence of and reasons for infertility were unclear in survivors of childhood cancer we conducted a two centre survey in 2006 and nationwide in 2008. In 2008/2009 we undertook a study entitled "Hormone and Sperm Analyses after Chemo- and Radiotherapy in Childhood and Adolescence". PATIENTS AND METHODS: Letters were sent to 748 former paediatric oncological patients who were at least 18 years of age at the time of the survey. Serum and sperm samples were analysed. RESULTS: We obtained 159 blood samples (86 women, 73 men). 42 men took part in the sperm analyses. The average participants' age at the time of the survey was 25 years. The anti-Mullerian hormone levels (AMH) in 14/86 female participants (16 %) were < 0.1 ng/ml. The follicular reserve of these women seemed manifestly impaired, which is consistent with suspected infertility. The AMH levels in 21/86 women (24 %) were 0.1 - 1.0 ng/ml indicating limited follicular reserve and therefore suspected early ovarian failure. Inhibin B levels of < 80 pg/ml and FSH levels of > 10 IU/L were found in 23/73 male participants (32 %), which may indicate impaired spermiogenesis with increased risk of infertility. 13/42 sperm analyses (31 %) revealed azoospermia. DISCUSSION: Paediatric oncological therapy seems to have led to fertility impairment in about 1/3 of the participants. Considering this serious impairment, patients and their families should be given comprehensive counselling ahead of therapy to enable fertility-preserving measures. For persons who wish to have children after undergoing therapy we recommend a hormone and sperm analysis. An early analysis may enable a more successful family planning.

[Intraosseous infusion. An important technique also for paediatric anaesthesia]. / Intraossäre Infusion. Eine wichtige Technik auch für die Kinderanästhesie.

Timely establishment of venous access in infants and toddlers can prove a particularly challenging task. Since the 1940s the technique of intraosseous infusion has established itself as a valuable alternative means for rapid, efficient and safe delivery of drugs and fluids to critically ill children. Whereas international guidelines for paediatric emergency medical care have assigned intraosseous infusion a high priority, most anaesthetists utilize this well-proven technique with great reluctance. This article describes the technique of intraosseous infusion, introduces two different cannulation systems, and discusses its potential indications in paediatric anaesthesia, based on current emergency medical care guidelines as well as some of our own case studies. In particular, children with acutely life-threatening conditions, such as circulatory arrest, laryngospasm, acute airway haemorrhage, hypovolaemic shock or hypothermia secondary to extensive burns, should receive an intraosseous cannula if intravenous access cannot be rapidly established. Future discussion may reveal whether a transiently inserted intraosseous infusion would also be indicated if the child with difficult or impossible venous access presents without acute life-threatening conditions for anaesthesia. Successful application of the intraosseous infusion technique requires immediate access to the necessary equipment, intensive education, continuous training and clear guidelines for its application in an anaesthesia department.

Dose finding in pediatric patients.

It is generally agreed that satisfactory safety and effectiveness of pharmaceutical products for children and adolescents have not yet been established. This applies in particular to anti-cancer drugs and even to those having successfully been used for many years in multidrug chemotherapy protocols for childhood cancer. For example, nephroblastoma or Wilms' tumor is one of the typical and frequent forms of childhood cancer occurring at a median age of about 3 years. Standard therapy for Wilms' tumor is the combination of vincristine and actinomycin D; survival is about 85%. For actinomycin D, the summary of product characteristics states that one contraindication is children aged below 6-12 months. If this would be considered and respected it would mean that a substantial proportion of children with Wilms' tumor would not be treated and thus a proven curative therapy would be withheld. The current situation in pediatrics is that off-label use has become a common practice: in private practice about 20% of prescriptions are off-label, in children's hospitals approximately 40%-50% with 50%-70% in pediatric oncology and more than 90% in neonatology (Conroy et al. 1999, 2000, 2003; Turner et al. 1996, 1998; McIntyre et al. 2000). These conditions are more or less tolerated by the authorities although they are beyond legality. The reason is that appropriate clinical trials like those in adults have not been conducted in children and drugs have therefore not been licensed.

[The results of a multicenter trial of acute lymphoblastic leukemia treatment on ALL-MB 91/ALL-BFM 90m in children: analysis of efficacy and toxicity].

AIM: A comparative analysis of efficacy and toxicity of two chemotherapy regimens: standard German protocol ALL-BFM 90m and less intensive original test protocol ALL-MB 91 in a multicenter trial of acute lymphoblastic leukemia (ALL) in children. MATERIAL AND METHODS: In 1995-2002 a total of 834 patients with newly diagnosed ALL aged 0-18 years were admitted to 10 clinics of Russia. Of them, 713 were randomized in two groups: treatment program ALL-BFM 90m (n = 355) and ALL-MB 91 program (n = 358). RESULTS: In 7-year follow-up median, 10-year event-free survival (EFS) and overall survival (OS) did not differ significantly between the groups and was 67 +/- 3 and 68 +/- 3% (ALL-MB 91) and 74 +/- 2, 71 +/- 3% (ALL-BFM 90m), respectively. Though the rate of isolated recurrences in CNS in patients on the protocol ALL-MB 91 was 2.8%, they developed only in 0.8% patients of the standard risk group. Anemia, thrombocytopenia and agranulocytosis developed less frequently, hospital stay was significantly shorter on the test protocol vs the control one (p < 0.01). CONCLUSION: EFS and OS on the test (ALL-MB 91) and control (ALL-BFM 90m) protocols were equivalent in lower toxicity and cost of therapy.

Treatment strategies and long-term results in paediatric patients treated in four consecutive AML-BFM trials.

A total of 1111 children with acute myeloblastic leukaemia (AML) were treated in four consecutive Berlin-Frankfurt-Münster (BFM) studies from 1978 to 1998. The first cooperative trial AML-BFM 78 established intensive chemotherapy with seven drugs, CNS irradiation and 2-year maintenance, achieving a long-term survival (overall survival (OS)) of 40%. Induction intensification in AML-BFM 83 resulted in significant improvement of disease-free survival (DFS). The risk of haemorrhage, especially in children with hyperleukocytosis, proved the high relevance of supportive care. In AML-BFM 87, the benefit of CNS irradiation in preventing CNS/systemic relapses was demonstrated. In AML-BFM 93, the introduction of idarubicin during first induction followed by intensification with HAM increased the 5-year EFS, DFS and OS to 50+/-2, 61+/-3 and 57+/-2%, respectively. Stem cell transplantation (SCT), as applied in high-risk patients with a matched related donor, did not significantly improve the outcome compared to chemotherapy alone. In spite of treatment intensification, the therapy-related death rate decreased from trial to trial, mainly during induction. The future aim is to reduce long-term sequelae, especially cardiotoxicity, by administration of less cardiotoxic drugs, and toxicity of SCT by risk-adapted indications. The AML-BFM studies performed in three European countries with >70 cooperating centres have significantly improved the outcome in AML children; nevertheless, increasing experience with these intensive treatment regimens is of fundamental importance to reduce fatal complications.

Mutations in the Nijmegen Breakage Syndrome gene (NBS1) in childhood acute lymphoblastic leukemia (ALL).

The Nijmegen Breakage Syndrome (NBS) is a rare autosomal recessive disorder associated with immune deficiency, chromosome fragility, and increased susceptibility to lymphoid malignancies. The aim of the present study was to elucidate the potential role of the gene mutated in NBS (NBS1) in the pathogenesis and disease progression of childhood acute lymphoblastic leukemia (ALL). Samples from 47 children with first relapse of ALL were analyzed for mutations in all 16 exons of the NBS1 gene, and in 7 of them (14.9%), four novel amino acid substitutions were identified. Mutations S93L, D95N, and I171V occur in the two known domains of nibrin that are probably involved in protein-protein interactions. Germ-line origin of the I171V mutation was confirmed in three patients, whereas the D95N exchange was present only in leukemic cells. The R215W mutation was observed in one ALL but also in a population-based study and probably represents a rare sequence variant. No additional mutations were found on the second allele in any of these seven patients. The observed NBS1 gene mutations in ALL patients points to its possible involvement in the pathogenesis of this disease.

Molecular quantification of response to therapy and remission status in TEL-AML1-positive childhood ALL by real-time reverse transcription polymerase chain reaction.

Although TEL-AML1 positivity [translocation t(12;21)(p13;q22)], detected in 20-25% of initial childhood acute lymphoblastic leukemia (ALL), has been associated with an excellent prognosis, its positive predictive value is insufficient for appropriate treatment stratification considering reported prevalence in relapsed ALL (3-28%). Molecular quantification of response to therapy by PCR-based methods has been shown to improve risk assessment. Here, we report on the sensitive quantification of leukemia-specific TEL-AML1 fusion transcript levels normalized to beta-actin expression (sensitivity threshholds, 10(-5)) by a novel real-time reverse transcription-PCR (RQ-RT-PCR) based on fluorescent TaqMan technique providing early and rapid evidence on the treatment efficacy of children with initial or relapsed TEL-AML1+ ALL enrolled in frontline or relapse trials of the Berlin-Frankfurt-Münster (BFM)-Study Group. In initial ALL, TEL-AML1/beta-actin decrease was > or =10(5)-fold in 50% of patients after induction therapy (day 33) and stayed TEL-AML1-negative throughout therapy, which suggested high sensitivity of leukemic cells to antineoplastic therapy. The remaining patients were still TEL-AML1+ before reintensification (ratios, 0.7 x 10(-2):10(-4)). In relapsed ALL, TEL-AML1/beta-actin decrease was generally less pronounced at corresponding time points, and conversion to TEL-AML1 negativity was observed in 40% of patients. Most notably, subsequent relapses occurred only among molecular poor responders, whereas all early responders remain in their second complete remission. In conclusion, real-time quantification of TEL-AML1/beta-actin kinetics distinguishes distinct molecular response groups, and provides indications capable of directing therapeutic interventions for patients with TEL-AML1+ ALL. Before considering modification of therapy, results should be interpreted cautiously taking into account the long duration of remission associated with TEL-AML1+ ALL.