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Biomedical subjects

Frank Berthold

Publications and source records attributed to Frank Berthold.

At least 19 recordsLinked to original sources

Differential expression of neuronal genes defines subtypes of disseminated neuroblastoma with favorable and unfavorable outcome.

PURPOSE: Identification of molecular characteristics of spontaneously regressing stage IVS and progressing stage IV neuroblastoma to improve discrimination of patients with metastatic disease following favorable and unfavorable clinical courses. EXPERIMENTAL DESIGN: Serial analysis of gene expression profiles were generated from five stage IVS and three stage IV neuroblastoma. Differential expression of candidate genes was evaluated by real-time quantitative reverse transcription-PCR in 76 pretreatment tumor samples (stage IVS n=27 and stage IV n=49). Gene expression-based outcome prediction was determined by Prediction Analysis for Microarrays using 38 tumors as a training set and 38 tumors as a test set. RESULTS: Comparison of serial analysis of gene expression profiles from stage IV and IVS neuroblastoma revealed approximately 500 differentially expressed transcripts. Genes related to neuronal differentiation were observed more frequently in stage IVS tumors as determined by associating transcripts to Gene Ontology annotations. Forty-one candidate genes were evaluated by quantitative reverse transcription-PCR and 18 were confirmed to be differentially expressed (P<or=0.001). Classification of patients according to expression patterns of these 18 genes using Prediction Analysis for Microarrays discriminated two subgroups with significantly differing event-free survival (96+/-6% versus 40+/-8% at 3 years; P<0.0001) and overall survival (100% versus 72+/-7% at 3 years; P=0.0003). This classifier was the only independent covariate marker in a multivariate analysis considering the variables stage, age, MYCN amplification, and gene signature. CONCLUSIONS: Spontaneously regressing and progressing metastatic neuroblastoma differ by specific gene expression patterns, indicating distinct levels of neuronal differentiation and allowing for an improved risk estimation of children with disseminated disease.

Child, Preschool↗

Loss in chromosome 11q identifies tumors with increased risk for metastatic relapses in localized and 4S neuroblastoma.

PURPOSE: To improve risk prediction in neuroblastoma and to specify the type of a possible relapse, alterations in the long arm of chromosome 11 were analyzed. EXPERIMENTAL DESIGN: A representative cohort of 611 neuroblastomas was investigated for deletion events in distal chromosome 11q using interphase fluorescence in situ hybridization. RESULTS: Alterations in 11q were found in 159 of 611 tumors in the whole cohort (26%) and were associated with stage 4 disease (P < 0.001) and age at diagnosis of >2.5 years (P < 0.001). Event-free survival and overall survival were significantly poorer for patients with 11q loss in the whole cohort (event-free survival and overall survival, P < 0.001) and in different subsets: neuroblastoma without MYCN amplification (MNA) (event-free survival and overall survival, P < 0.001), with MNA (event-free survival, P = 0.03; overall survival, P = 0.02), and MYCN-nonamplified stage 1, 2, 3, and 4S tumors with and without del 1p (event-free survival and overall survival, P < 0.001). In stage 4, the 11q status did not discriminate outcome. By multivariate analysis, the 11q status proved prognostic for event-free survival in the whole cohort (P = 0.008; hazard ratio, 1.573) and in the subgroup of stages 1, 2, 3, and 4S without MNA (P < 0.001; hazard ratio, 3.534). Moreover, 11q alterations were strongly correlated with the occurrence of metastatic relapses (P < 0.001). CONCLUSION: In addition to the current risk stratification, the status of 11q enables the identification of patients with an increased risk for relapses in general and metastatic relapses in particular.

Adolescent↗

Electric cell-substrate impedance sensing with screen printed electrode structures.

Impedance sensors in thick film technology have been tested as a tool for electric cell-substrate impedance sensing. The screen printed Pt electrodes have a width of 250-400 microm. Electrodes and the surrounding ceramic chip substrate could be homogeneously grown with L-929 and Hela cells. The performance of a screen printed interdigitated electrode structure (IDES) was compared with that of thin film structures with the same layout geometry. The thick film impedance sensors allowed to correctly record the morphological response of confluent Hela cell layers to stimulation with histamine. A thick film conductivity sensor also revealed impedance values which were dependent on cell growth on the electrode surface, even at a very low frequency range of approximately 1 Hz.

Animals↗

Treatment options in childhood pontine gliomas.

BACKGROUND: Pontine gliomas are the subgroup of brainstem gliomas with the worst prognosis. Controversial treatment approaches are discussed. PATIENTS AND METHODS: Data of children with pontine gliomas treated in different prospective multi-center studies who were registered in the HIT-GBM database were pooled and analyzed addressing prognostic factors and the relevance of intensive treatment using contingency tables, Kaplan-Meier curves and Cox regression analyses. RESULTS: From 1983 to 2001, 153 patients (74 males, 79 females, mean age: 8.1 years) with pontine gliomas were registered. Twenty-one tumors were low-grade and 60 were high-grade gliomas (72 undefined histology: 67 no surgery, 5 incomplete data). Sixteen tumors were partially resected, and 125 were irradiated. Ninety children received chemotherapy according to the "HIT-GBM" protocols ("Hirntumor-Glioblastoma multiforme"). The one-year overall survival rate (1YOS) of all patients with pontine glioma was 39.9+/-4.3%. None of the surviving patients had an observation time longer than 3.9 years. Favorable prognostic factors seemed to be age younger than 4 years, low-grade histology and smaller tumor. All three major treatment modalities including resection, irradiation and chemotherapy had prognostic relevance in univariable analysis. Chemotherapy remained beneficial, even if the analysis was restricted to the subgroup of irradiated tumors (1YOS 45.8+/-5.4% vs. 34.4+/-13.5%, P=0.030). CONCLUSION: Irradiation is an effective element for the treatment of pontine gliomas. Intensive chemotherapy seems to be important in achieving a better OS.

Age Factors↗

Reduced expression of CAMTA1 correlates with adverse outcome in neuroblastoma patients.

PURPOSE: A distal portion of 1p is frequently deleted in human neuroblastomas, and it is generally assumed that this region harbors at least one gene relevant for neuroblastoma development. A 1p36.3 commonly deleted region, bordered by D1S2731 and D1S214 has been defined. The present study surveys whether expression of genes mapping to this region is associated with tumor behavior. EXPERIMENTAL DESIGN: Candidate genes localized within the deleted region were identified by sequence data analysis. Their expression was assessed in a cohort of 49 primary neuroblastomas using cDNA microarray analysis. Gene expression patterns associated with known prognostic markers and patient outcome were further evaluated by quantitative real-time reverse transcription-PCR in a cohort of 102 neuroblastomas. RESULTS: The commonly deleted region spans 261 kb and encompasses two genes, FLJ10737 and CAMTA1. We found no evidence for an association of FLJ10737 expression with established prognostic variables or outcome. In contrast, low CAMTA1 expression characterized tumors with 1p deletion, MYCN amplification, and advanced tumor stages 3 and 4. Moreover, low CAMTA1 expression was significantly associated with poor outcome (P < 0.001). In multivariate analysis of event-free survival, the prognostic information of low CAMTA1 expression was independent of 1p status, MYCN status, tumor stage, and age of the patient at diagnosis (hazard ratio, 3.52; 95% confidence interval, 1.21-10.28; P = 0.02). CONCLUSIONS: Our data suggest that assessment of CAMTA1 expression may improve the prognostic models for neuroblastoma and that it will be important to define the biological function of CAMTA1 in this disease.

Age Factors↗

Oligonucleotide array-based comparative genomic hybridization (aCGH) of 90 neuroblastomas reveals aberration patterns closely associated with relapse pattern and outcome.

The study of genomic alterations in neuroblastoma is of particular importance since several cytogenetic markers proved to be closely associated with the clinical phenotype. To disclose patterns of gains and losses, we performed high-resolution oligonucleotide array-based comparative genomic hybridization (aCGH). A total cohort of 90 patients was classified into 6 subsets according to tumor stage and outcome: Stages 1-3+ (with event), Stage 1-3- (no event), Stage 4+/-, and Stage 4S+/-. The aberration patterns in Stages 1-3- and 4S- tumors differed from all other groups as they were predominantly characterized by losses (3, 4, 14, X) and gains (7, 17) of whole chromosomes. However, 59/65 (91%) tumors of Stages 1-3+ or Stage 4 revealed numerous structural copy number alterations (sCNA). While deletions in chromosomes 1, 3, and 11 discriminated outcome in Stage 4, there were no specific sCNA that distinguished tumor stage within the subgroup of unfavorable tumors. sCNA in 1p, 3p, 11q, 17q, or MYCN amplification (MNA) was seen among 22/24 patients who died, 10/12 with metastatic relapses, and 5/9 with local recurrences. Detailed breakpoint analyses on chromosomes 1, 3, 11, and 17 disclosed preferred breaking areas, although breakpoints were not identical. Amplifications were found in 18 patients and involved 2p24 (MYCN) and other segments of chromosome 2, as well as regions on chromosome arms 6q, 12q, and 17q. One single feature in 21q21.1 (BU678720, without known function yet) attracted particular attention since five patients showed a homozygous loss of this sequence.

Chromosome Aberrations↗

Intensified external-beam radiation therapy improves the outcome of stage 4 neuroblastoma in children > 1 year with residual local disease.

BACKGROUND AND PURPOSE: In neuroblastoma, the value of radiation therapy in high-intensive first-line treatment protocols is still not exactly known but radiation-associated long-term effects need to be considered. The impact of external-beam radiation therapy (EBRT) on event-free (EFS) and overall survival (OS) of stage 4 neuroblastoma patients of the NB97 trial was analyzed. PATIENTS AND METHODS: The authors retrospectively analyzed data of 110 stage 4 neuroblastoma patients > or = 1 year who underwent induction therapy and high-dose chemotherapy with stem cell transplantation without relapse. Intensified local EBRT (36 Gy) of the residual tumor volume was reserved for patients with residual viable tumor documented by MRI and corresponding metaiodobenzylguanidine (MIBG) uptake. RESULTS: 13 patients who received EBRT for local residual disease had similar outcome (3-year EFS 85 +/- 10%, 3-year OS 92 +/- 7%) as 74 patients without any MIBG residual (3-year EFS 61 +/- 6%, 3-year OS 75 +/- 6%). Outcome was worse in 23 children without EBRT to residual primary (3-year EFS 25 +/- 10%, 3-year OS 51 +/- 11%). Separate analysis of 14 patients with isolated localized residual disease found far better outcome of eight patients with EBRT (3-year EFS 100%, 3-year OS 100%) compared to six patients without EBRT (3-year EFS 20 +/- 18%, 3-year OS 20 +/- 18%). Multivariate analysis identified EBRT as influential on EFS (hazard ratio 0.27) and OS (hazard ratio 0.17) in addition to MYCN amplification and presence of primary tumor site MIBG residual. CONCLUSION: EBRT appeared effective in high-intensive treatment of stage 4 neuroblastoma. It seems to compensate the disadvantage of incomplete response to induction chemotherapy. These retrospective results need confirmation by a prospective randomized trial.

Child↗

Favorable outcome of triploid neuroblastomas: a contribution to the special oncogenesis of neuroblastoma.

There is a well-known association between patient outcome and tumor ploidy in neuroblastoma. To date, however, most clinical trials have not used this parameter for therapy stratification. Using conventional cytogenetics and fluorescence in situ hybridization (FISH), we investigated 36 tumors in terms of ploidy and chromosome 1 copy number (polysomy). In addition, interphase FISH for polysomy was performed on a second cohort of 440 neuroblastomas, together with the status of 1p, MYCN, and 11q. The main goals were as follows: (1) to assess the reliability of FISH to determine ploidy; (2) to illustrate associations between somy 1 and clinical/biologic factors; and (3) to investigate the role of somy 1 for predicting outcome. The comparison between karyotyping and FISH in the smaller cohort revealed 86% consistency between ploidy and polysomy (31/36). According to FISH, trisomic tumors in the second cohort showed structural chromosomal aberrations less frequently compared to di-/tetrasomic tumors (15 vs. 60%, P < 0.001). The portion of trisomic neuroblastomas was higher in stages 1, 2, and 4S versus stages 3 and 4 (55 vs. 24%, P < 0.001) and in children 18 months or younger versus those older than 18 months (55 vs. 19%, P < 0.001). Prognosis was significantly better for trisomic tumors versus di-/tetrasomic in the whole cohort [event-free (EFS) and overall survival (OS), P < 0.001]. In the subgroup without abnormalities of other molecular markers, EFS of trisomic neuroblastomas was better (P = 0.048), but was most likely due to an unequal stage distribution. In further subgroups, in terms of age and stage, significance between the somy groups was not reached, neither for EFS nor OS. The multivariate analyses including age, stage, chromosomal markers, and somy 1 confirmed the lack of independent prognostic power for the copy number of chromosome 1. This study demonstrates the following: (1) FISH is a practical alternative to other more labor-intensive techniques for determining ploidy; (2) trisomic tumors correlate with younger age at diagnosis, localized stage, and the lack of structural alterations; and (3) polysomy is not an independent prognostic marker. The sharp decline of trisomic tumors after the age of 18 months supports the idea of different genetic tumor entities.

Age of Onset↗

Localization of 131I-labelled monoclonal antibody ERIC1 in a subcutaneous xenograft model of neuroblastoma in SCID mice.

PURPOSE: To evaluate a novel strategy of immunolocalization of human neuroblastoma by targeting the neural cell adhesion molecule (NCAM), which is over-expressed on neuroblastoma. METHODS: NCAM expression on the cell surface of established neuroblastoma cells was shown by flow cytometry. A SCID mouse model using IMR5-75 neuroblastoma cells to induce subcutaneous tumour growth was established. 131I was used to label monoclonal NCAM specific ERIC1 antibodies generating the 131I-ERIC1 antibody, which showed a high affinity to NCAM also after labelling (KD=9 x 10(-8) mol . l(-1)). RESULTS: Measurement of organ-specific radioactivity showed low organ-specific uptake (5.33%ID/g (percent of injected dose per gram of tissue) after 72 h), which continuously decreased over the 96 h investigation period, demonstrating clearance of radioactivity. In contrast, tumours accumulated radioactivity continuously up to a peak of 42.07%ID/g at the 96 h time point (31.07%ID/g at 72 h). This specific uptake could be blocked by application of unlabelled ERIC1 antibodies. Measurement of blood specific radioactivity revealed a characteristic clearance over the first 72 h. With 37 Gy, tumour-specific radioactivity reached therapeutic doses after 96 h. CONCLUSIONS: These results indicate that 131I-labelled ERIC1 has the ability to probe NCAM-expressing tumour cells in vivo with high efficiency and is a promising reagent for the diagnosis and treatment of NCAM-positive human tumours, especially for neuroblastoma.

Animals↗

The role of age in neuroblastoma risk stratification: the German, Italian, and children's oncology group perspectives.

Recent evidence suggests that the cut-off for age utilized in neuroblastoma risk groups should be increased from the 365-day cut-off currently in use. Separate cooperative group analyses were performed by German and Italian groups and two analyses by the Children's Oncology Group (North America, Australia, New Zealand, Switzerland, Netherlands). In general, the results are in agreement regarding the prognostic contribution of age. There is strong evidence to support an increase in the age cut-off to a value in the range of 15-18 months based on the results from the German analysis and two COG analyses. However, Italian results in INSS stage 4 patients show that outcome in patients 12-17 months is not better than that of older patients. Further analyses are warrented.

Age Factors↗

Characterization of a complex genomic alteration on chromosome 2p that leads to four alternatively spliced fusion transcripts in the neuroblastoma cell lines IMR-5, IMR-5/75 and IMR-32.

Genetic aberrations in neuroblastoma (NB) have been extensively characterized over the last years. Alterations of the short arm of chromosome 2 (2p) have been of particular interest, since amplification of the MYCN oncogene on 2p24 is associated with an adverse outcome in NB patients. Here, we report on the characterization of a novel genomic rearrangement involving genetic material from 2p13 and 2p24 in NB cell lines that was discovered based on a serial analysis of gene expression (SAGE) profile of the MYCN-amplified NB cell line IMR-5. By analysis of a highly expressed SAGE tag not matching a Unigene cluster we identified four alternatively spliced corresponding transcripts, each of which consisted of the first 14 exons of the anthrax toxin receptor 1 gene (2p13.1) and varying combinations of exons of an unidentified gene located 1.3 Mb telomeric of MYCN (2p24.3) that was termed novel neuroblastoma gene 1. By Southern Blotting, Fluorescent In Situ Hybridization and Long Distance Inverse-PCR we disclosed that these transcripts result from a genomic alteration including material from distinct regions of chromosome 2p and four genomic breakpoints that are joined by short sequences of unknown origin. Furthermore, we show that this rearrangement lies within the homogeneous staining regions (HSR) in IMR-32 cells and is prevalent in both IMR-32 cells and their sub-clones IMR-5 and IMR-5/75, but not in a panel of 70 primary NB tumors. Our work is the first study discovering a fusion transcript based on a SAGE profile and for the first time precisely describes the DNA sequence of amplified breakpoint regions in NB.

Alternative Splicing↗

Risk estimation in localized unresectable single copy MYCN neuroblastoma by the status of chromosomes 1p and 11q.

In localized neuroblastoma, the identification of patients requiring intensive treatment is still difficult. We retrospectively analyzed data of 280 single copy MYCN stage 2 and 3 neuroblastoma patients with gross residual tumor after initial surgery. The 3-year-event free survival of the total group was 83+/-2%, and 3-year-overall survival was 92+/-2%. Patients < or=1.5 years had a better outcome than older children. Deletions/imbalances of chromosome 1p were found in 9/90 patients and were associated with a higher event rate but not with a higher death rate. Aberrations of chromosome 11q in 14/91 patients were correlated with a higher event and death rate. Multivariate analysis identified 1p aberrations as important for event free survival and 11q aberrations for overall survival.

Adolescent↗

Lacking immunocytological GD2 expression in neuroblastoma: report of 3 cases.

Immunocytological bone marrow assessment for contamination with neuroblastoma cells is based on their characteristic GD2 surface staining. Neuroblastoma without GD2 expression have been rarely and only after antibody therapy reported. Conventional cytology was performed using Pappenheim staining. For immunocytology, the APAAP method was utilized with the 14G2a anti-GD2 mouse monoclonal antibody. 7 x 10(5) cells on cytospin preparations were investigated. In 2003, 288 bone marrow samples from 191 neuroblastoma patients were investigated by cytology and immunocytology. Three cases demonstrated GD2 negativity on cytologically unambiguous neuroblastoma cells. Two female cases (94 and 37 months of age) with stage 4 neuroblastoma had GD2 expressing neuroblastoma cells in bone marrow at diagnosis. At 2nd relapse 25 and 23 months after diagnosis and 8 months and 12 months after anti-GD2 antibody treatment (ch14.18), the bone marrow infiltrating neuroblastoma cells lacked GD2 staining. The third patient, a 63-month-old girl with bone marrow replacement by neuroblastoma cells showed at diagnosis a mixture of GD2-unstained tumor clumps and very weakly stained neuroblastoma cells. Neuroblastoma cells may lack GD2 expression at diagnosis and at recurrence. This observation has diagnostic and therapeutic implications.

Antibodies, Monoclonal↗

Esthesioneuroblastoma in childhood and adolescence. Better prognosis with multimodal treatment?

BACKGROUND AND PURPOSE: Only 3% of all malignant intranasal tumors are esthesioneuroblastomas (ENB) and only 20% of these rare neuroectodermal tumors are diagnosed up to 20 years of age. Radiotherapy and surgery are established treatment modalities for these patients, but the role of chemotherapy, especially in a multimodal approach, is not well defined. To investigate the influence of radio- and chemotherapy, the treatment and course of the disease in children and adolescents with ENB were analyzed retrospectively. PATIENTS AND METHODS: 19 unselected patients (nine male and ten female) diagnosed with ENB < or = 20 years of age were included in this analysis. Median age at diagnosis was 14.0 years (range, 5-20 years). The tumors were Kadish stage B in 4/19 patients and stage C in 15/19 patients. 17 patients underwent surgery, either without further therapy (n = 4), followed by radiotherapy (n = 1) or as part of multimodal regimens (n = 12). Two patients received radio- and chemotherapy without surgery. Complete resection (R0) was achieved in 15 out of 17 patients with surgery including all five patients with preoperative chemotherapy due to unresectable primary at diagnosis. RESULTS: The 5-year overall survival (OS) for the whole group was 73% +/- 12% and the 5-year event-free survival (EFS) 55% +/- 13%. None of the four patients with stage B experienced tumor progression so far, whereas seven out of 15 patients with stage C did (5-year EFS 47% +/- 14%; not significant). Patients with Kadish stage C and multimodal treatment strategies combing surgery, chemo- and radiotherapy had a significantly better outcome than patients with stage C and less than three treatment modalities (65% +/- 17% vs. 20% +/- 18%; p = 0.02). CONCLUSION: These data indicate a benefit of multimodal treatment regimens combining surgery, chemo- and radiotherapy for pediatric patients with ENB Kadish stage C. Chemotherapy appears to improve resectability, EFS, and OS. Radiotherapy is an integral part in the management of children and young adolescents with ENB in Kadish stage B and C.

Adolescent↗

Primary dissemination of high-grade gliomas in children: experiences from four studies of the Pediatric Oncology and Hematology Society of the German Language Group (GPOH).

PURPOSE: Clinical data on central nervous system (CNS) dissemination of high-grade gliomas (HGG) at initial presentation in children are rare. PATIENTS AND METHODS: We conducted a retrospective data analysis of all patients enrolled into four consecutive HGG protocols of the Pediatric Oncology and Hematology Society of the German Language Group (GPOH) to determine the incidence of primary CNS dissemination of HGG and to describe clinical characteristics and outcome of children with HGG who were diagnosed with CNS dissemination at initial presentation. 546 patients with newly diagnosed HGG (n=348) or diffuse intrinsic pontine gliomas (n=198) were enrolled in these four studies. Data concerning tumor dissemination are available from 324 patients. RESULTS: A total of 10 patients (3.1%) (anaplastic astrocytoma: n=3, glioblastoma multiforme: n=6, diffuse intrinsic pontine glioma: n=1) had primary tumor dissemination. Median age at diagnosis was 9.3 years (range: 0.3-21.3 years). The most frequent primary tumor sites were the cortex (n=4), followed by the ventricles (n=2), cerebellum (n=1), spinal cord (n=1), and pons (n=1). One patient had diffuse gliomatosis cerebri. Following surgery eight patients received local radiotherapy and eight additional chemotherapy. At a median follow-up of 10 months (range: 0.05-3 years) four patients are alive. None is disease-free. Median progression-free and overall survival was 0.8 years (95% CI 0.2-1.4) and 1.5 years (95% CI 0.67-2.29) for patients with primary tumor dissemination, respectively, with no statistically significant differences between the group with and the group without primary tumor dissemination. CONCLUSIONS: Initial diagnostic evaluation should include complete CNS imaging as well as cerebrospinal fluid examination in all patients with HGG. As prognosis of children with HGG and primary CNS dissemination was not inferior to patients without dissemination in our population, these patients should be treated in the same way as patients without primary CNS dissemination.

Adolescent↗

Myeloablative megatherapy with autologous stem-cell rescue versus oral maintenance chemotherapy as consolidation treatment in patients with high-risk neuroblastoma: a randomised controlled trial.

BACKGROUND: Myeloablative megatherapy is commonly used to improve the poor outlook of children with high-risk neuroblastoma, yet its role is poorly defined. We aimed to assess whether megatherapy with autologous stem-cell transplantation could increase event-free survival and overall survival compared with maintenance chemotherapy. METHODS: 295 patients with high-risk neuroblastoma (ie, patients with stage 4 disease aged older than 1 year or those with MYCN-amplified tumours and stage 1, 2, 3, or 4S disease or stage 4 disease and <1 year old) were randomly assigned to myeloablative megatherapy (melphalan, etoposide, and carboplatin) with autologous stem-cell transplantation (n=149) or to oral maintenance chemotherapy with cyclophosphamide (n=146). The primary endpoint was event-free survival. Secondary endpoints were overall survival and the number of treatment-related deaths. Analyses were done by intent to treat, as treated, and treated as randomised. FINDINGS: Intention-to-treat analysis showed that patients allocated megatherapy had increased 3-year event-free survival compared with those allocated maintenance therapy (47% [95% CI 38-55] vs 31% [95% CI 23-39]; hazard ratio 1.404 [95% CI 1.048-1.881], p=0.0221), but did not have significantly increased 3-year overall survival (62% [95% CI 54-70] vs 53% [95% CI 45-62]; 1.329 [0.958-1.843], p=0.0875). Improved 3-year event-free survival and 3-year overall survival were also recorded for patients given megatherapy in the as-treated group (n=212) and in the treated-as-randomised group (n=145). Two patients died from therapy-related complications during induction treatment. No patients given maintenance therapy died from acute treatment-related toxic effects. Five patients given megatherapy died from acute complications related to megatherapy. INTERPRETATION: Myeloablative chemotherapy with autologous stem-cell transplantation improves the outcome for children with high-risk neuroblastoma despite the raised risk of treatment-associated death.

Adolescent↗

Reliable transcript quantification by real-time reverse transcriptase-polymerase chain reaction in primary neuroblastoma using normalization to averaged expression levels of the control genes HPRT1 and SDHA.

Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) represents a sensitive and efficient technique to determine expression levels of target genes in multiple samples and is increasingly used in clinical oncology to evaluate the patient's outcome or to detect minimal residual disease. Normalization of raw data are required to obtain comparable results between different specimens and is usually achieved by correlating transcript abundances of target genes with those of a single control gene with putatively stable expression levels. In this study, expression stability of six supposed control genes was evaluated in 64 samples of primary neuroblastoma and HPRT1 and SDHA mRNA levels were shown to exhibit the least expression variability among the samples. Because application of more than one control gene may enhance reliability of real-time RT-PCR results, various normalization factors consisting of the geometrical mean of multiple control gene expression values were calculated and evaluated by mRNA quantification of 14 target genes. Comparison with transcript levels determined by oligonucleotide-array expression analysis revealed that target gene mRNA quantification became most consistent after normalization to averaged expression levels of HPRT1 and SDHA. This normalization factor was in addition demonstrated to be not associated with stage of disease or MYCN amplification status of the tumor. Thus, these data indicate that the geometrical mean of HPRT1 and SDHA transcript levels represents a suitable internal control for biological and clinical studies investigating differential gene expression in primary neuroblastoma by real-time RT-PCR.

Gene Expression↗