Observation of magnetic skyrmions in unpatterned symmetric multilayers at room temperature and zero magnetic field.

Magnetic skyrmions are promising candidates for the next generation of spintronic devices due to their small size and topologically protected structure. One challenge for using these magnetic states in applications lies on controlling the nucleation process and stabilization that usually requires an external force. Here, we report on the evidence of skyrmions in unpatterned symmetric Pd/Co/Pd multilayers at room temperature without prior application of neither electric current nor magnetic field. Decreasing the ferromagnetic interlayer thickness, the tuning of the physical properties across the ferromagnetic/non-magnetic interface gives rise to a transition from worm like domains patterns to isolated skyrmions as demonstrated by magnetic force microscopy. On the direct comparison of the measured and simulated skyrmions size, the interfacial Dzyaloshinskii-Moriya interaction (iDMI) was estimated, reveling that isolated skyrmions are just stabilized at zero magnetic field taking into account non-null values of iDMI. Our findings provide new insights towards the use of stabilized skyrmions for room temperature devices in nominally symmetric multilayers.

Brazilian Pampa Biome Honey Protects Against Mortality, Locomotor Deficits and Oxidative Stress Induced by Hypoxia/Reperfusion in Adult Drosophila melanogaster.

We aimed to investigate the potential beneficial effects of the Brazilian Pampa biome honey in a Drosophila-based hypoxia model. Adult flies were reared in standard medium in the presence or absence of honey (at a final concentration of 10 % in medium). Then, control flies (4 % sucrose in medium) and honey-treated flies were submitted to hypoxia. Subsequently, flies were analyzed for mortality, neurolocomotor behavior (negative geotaxis), mitochondrial/oxidative stress parameters and expression of hypoxia/stress related genes by RT-qPCR. The HPLC analysis revealed the presence of phenolics and flavonoids in the studied honey. Caffeic acid was the major compound followed by p-coumaric acid and kaempferol. The presence of such compounds was correlated with a substantial antioxidant activity in vitro. Flies subjected to hypoxia presented marked mortality, locomotor deficits and changes in oxidative stress and mitochondrial activity parameters. Honey treatment was able to completely block mortality and locomotor phenotypes. In addition, honey was able to reverse ROS production and hypoxia-induced changes in mitochondrial complex I and II activity. Hypoxia also induced an up-regulation in mRNA expression of Sima (HIF-1), NFκß, NRF2, HOX, AKT-1, InR, dILP2, dILP5 and HSP27. Honey treatment was not able to modulate changes in the tested genes, indicating that its protective effects involve additional mechanisms other than transcriptional activity of hypoxia-driven adaptive responses in flies. Our results demonstrated, for the first time, the beneficial effects of honey against the deleterious effects of hypoxia/reperfusion processes in a complex organism.

Augmented expression of MYC and/or MYCN protein defines highly aggressive MYC-driven neuroblastoma: a Children's Oncology Group study.

BACKGROUND: MYCN amplification with subsequent MYCN protein overexpression is a powerful indicator of poor prognosis of neuroblastoma patients. Little is known regarding the prognostic significance of the homologous MYC protein expression in neuroblastoma. METHODS: Immunostaining for MYCN and MYC protein was performed on 357 undifferentiated/poorly differentiated neuroblastomas. Results were analysed with other prognostic markers. RESULTS: Sixty-seven (19%) tumours were MYCN(+), 38 (11%) were MYC(+), and one(0.3%) had both proteins(+). MYCN(+) tumours and MYC(+) tumours were more likely diagnosed in children>18months with stage4-disease. MYCN(+) tumours were associated with amplified MYCN, Unfavourable Histology (UH), and High-MKI (Mitosis-Karyorrhexis Index). MYC(+) tumours were also frequently UH but not associated with MYCN amplification, and more likely to have low-/intermediate-MKI. Favourable Histology patients without MYC/MYCN expressions exhibited the best survival (N=167, 89.7±5.5% 3-year EFS, 97.0±3.2% 3-year OS), followed by UH patients without MYC/MYCN expressions (N=84, 63.1±13.6% 3-year EFS, 83.5±9.4% 3-year OS). MYCN(+)patients and MYC(+)patients had similar and significantly low (P<0.0001) survivals (46.2±12.0% 3-year EFS, 63.2±12.1% 3-year OS and 43.4±23.1% 3-year EFS, 63.5±19.2% 3-year OS, respectively). Notably, the prognostic impact imparted by MYC expression was independent from other markers. CONCLUSIONS: In this series, ∼30% of neuroblastomas had augmented MYCN or MYC expression with dismal survivals. Prospective study of MYC/MYCN protein expression signature as a new biomarker for high-risk neuroblastomas should be conducted.

Cytotoxicity of CD56-positive lymphocytes against autologous B-cell precursor acute lymphoblastic leukemia cells.

Precursor B-lineage acute lymphoblastic leukemia (pre-B ALL) affects hematopoietic development and therefore is associated with immune deficiencies that can be further exacerbated by chemotherapy. It is unclear if and when monoclonal antibodies (mAbs) that stimulate antibody-mediated cellular cytotoxicity (ADCC) can be used for treatment because this depends on the presence of functional effector cells. Here, we used flow cytometry to determine that patient samples at diagnosis, post-induction and relapse contain detectable numbers of CD56+ cells. We were able to selectively expand CD56+ immune effector cells from bone marrow and peripheral blood samples at diagnosis and at various stages of treatment by co-culture with artificial antigen-presenting K562 clone 9.mbIL-21 cells. Amplified CD56+CD3- cells had spontaneous and anti-B cell-activating factor receptor mAb-stimulated ADCC activity against allogeneic ALL cells, which could be further enhanced by IL-15. Importantly, matched CD56+ effector cells also killed autologous ALL cells grown out from leukemia samples of the same patient, through both spontaneous as well as antibody-dependent cellular cytotoxicity. Since autologous cell therapy will not be complicated by graft-versus-host disease, our results show that expanded CD56+ cells could be applied for treatment of pre-B ALL without transplantation, or for purging of bone marrow in the setting of autologous bone marrow transplants.

[Consensus recommendations for the assessment of fitness to drive in cognitively impaired patients]. / Konsensusempfehlungen zur Beurteilung der medizinischen Mindestanforderungen für Fahreignung bei kognitiver Beeinträchtigung.

Memory Clinics provide evidence based diagnosis and treatment of dementia. Whenever a diagnosis of dementia is made, it is important to inform the patients about the possible impact of dementia on driving. Patients and their next of kin require competent advice whenever this difficult question is addressed and the mobility desire and the risks related to driving need to be carefully weight up. The time of diagnosis does not necessarily equate to the time when a person with dementia becomes an unsafe driver. The cause and severity of dementia, comorbidities and the current medication need to be carefully taken into account for this decision. On behalf of the association of the Swiss Memory Clinics, a group of experts has developed recommendations to assess fitness to drive in cognitively impaired older adults.

Antibody targeting of anaplastic lymphoma kinase induces cytotoxicity of human neuroblastoma.

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase aberrantly expressed in neuroblastoma, a devastating pediatric cancer of the sympathetic nervous system. Germline and somatically acquired ALK aberrations induce increased autophosphorylation, constitutive ALK activation and increased downstream signaling. Thus, ALK is a tractable therapeutic target in neuroblastoma, likely to be susceptible to both small-molecule tyrosine kinase inhibitors and therapeutic antibodies-as has been shown for other receptor tyrosine kinases in malignancies such as breast and lung cancer. Small-molecule inhibitors of ALK are currently being studied in the clinic, but common ALK mutations in neuroblastoma appear to show de novo insensitivity, arguing that complementary therapeutic approaches must be developed. We therefore hypothesized that antibody targeting of ALK may be a relevant strategy for the majority of neuroblastoma patients likely to have ALK-positive tumors. We show here that an antagonistic ALK antibody inhibits cell growth and induces in vitro antibody-dependent cellular cytotoxicity of human neuroblastoma-derived cell lines. Cytotoxicity was induced in cell lines harboring either wild type or mutated forms of ALK. Treatment of neuroblastoma cells with the dual Met/ALK inhibitor crizotinib sensitized cells to antibody-induced growth inhibition by promoting cell surface accumulation of ALK and thus increasing the accessibility of antigen for antibody binding. These data support the concept of ALK-targeted immunotherapy as a highly promising therapeutic strategy for neuroblastomas with mutated or wild-type ALK.

Consensus criteria for sensitive detection of minimal neuroblastoma cells in bone marrow, blood and stem cell preparations by immunocytology and QRT-PCR: recommendations by the International Neuroblastoma Risk Group Task Force.

Disseminating disease is a predictive and prognostic indicator of poor outcome in children with neuroblastoma. Its accurate and sensitive assessment can facilitate optimal treatment decisions. The International Neuroblastoma Risk Group (INRG) Task Force has defined standardised methods for the determination of minimal disease (MD) by immunocytology (IC) and quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR) using disialoganglioside G(D2) and tyrosine hydroxylase mRNA respectively. The INRG standard operating procedures (SOPs) define methods for collecting, processing and evaluating bone marrow (BM), peripheral blood (PB) and peripheral blood stem cell harvest by IC and QRT-PCR. Sampling PB and BM is recommended at diagnosis, before and after myeloablative therapy and at the end of treatment. Peripheral blood stem cell products should be analysed at the time of harvest. Performing MD detection according to INRG SOPs will enable laboratories throughout the world to compare their results and thus facilitate quality-controlled multi-centre prospective trials to assess the clinical significance of MD and minimal residual disease in heterogeneous patient groups.

Evidence for an age cutoff greater than 365 days for neuroblastoma risk group stratification in the Children's Oncology Group.

PURPOSE: In the Children's Oncology Group, risk group assignment for neuroblastoma is critical for therapeutic decisions, and patients are stratified by International Neuroblastoma Staging System stage, MYCN status, ploidy, Shimada histopathology, and diagnosis age. Age less than 365 days has been associated with favorable outcome, but recent studies suggest that older age cutoff may improve prognostic precision. METHODS: To identify the optimal age cutoff, we retrospectively analyzed data from the Pediatric Oncology Group biology study 9047 and Children's Cancer Group studies 321p1-p4, 3881, 3891, and B973 on 3,666 patients (1986 to 2001) with documented ages and follow-up data. Twenty-seven separate analyses, one for each different age cutoff (adjusting for MYCN and stage), tested age influence on outcome. The cutoff that maximized outcome difference between younger and older patients was selected. RESULTS: Thirty-seven percent of patients were younger than 365 days, and 64% were > or = 365 days old (4-year event-free survival [EFS] rate +/- SE: 83% +/- 1% [n = 1,339] and 45% +/- 1% [n = 2,327], respectively; P < .0001). Graphical analyses revealed the continuous nature of the prognostic contribution of age to outcome. The optimal 460-day cutoff we selected maximized the outcome difference between younger and older patients. Forty-three percent were younger than 460 days, and 57% were > or = 460 days old (4-year EFS rate +/- SE: 82% +/- 1% [n = 1,589] and 42% +/- 1% [n = 2,077], respectively; P < .0001). Using a 460-day cutoff (assuming stage 4, MYCN-amplified patients remain high-risk), 5% of patients (365 to 460 days: 4-year EFS 92% +/- 3%; n = 135) fell into a lower risk group. CONCLUSION: The prognostic contribution of age to outcome is continuous in nature. Within clinically relevant risk stratification, statistical support exists for an age cutoff of 460 days.

Expression of CD1d by myelomonocytic leukemias provides a target for cytotoxic NKT cells.

Natural killer T (NKT) cells with an invariant T-cell receptor for alpha-galactosylceramide (alphaGalCer) that is presented by CD1d have been reported to be cytotoxic for myelomonocytic leukemia cells. However, the necessity for leukemia cell CD1d expression, the role of alphaGalCer, and the cytotoxic mechanisms have not been fully elucidated. We evaluated these issues with myeloid leukemia cells from 14 patients and purified NKT cells that were alphaGalCer/CD1d reactive. CD1d was expressed by 80-100% of cells in three of seven acute myeloid leukemias (AMLs) and by 28-77% of cells in five of six juvenile myelomonocytic leukemias (JMML). CD1d+ AML cells were myelomonocytic or monoblastic types, and CD1d+ JMML cells were differentiated and CD34-. Cytotoxicity required leukemia cell CD1d expression and was increased by alphaGalCer (P<0.0001) and inhibited by anti-CD1d mAb (P<0.001). The perforin/granzyme-B pathway of NKT cells caused up to 85% of cytotoxicity, and TNF-alpha, FASL, and TRAIL mediated additional killing. CD56+ NKT cells expressed greater perforin and were more cytotoxic than CD56 NKT cells without alphaGalCer (P<0.0001), but both subpopulations were highly and equally cytotoxic in the presence of alphaGalCer. We conclude that CD1d expression is stage-specific for myelomonocytic leukemias and could provide a target for NKT-cell-mediated immunotherapy.

Histopathology (International Neuroblastoma Pathology Classification) and MYCN status in patients with peripheral neuroblastic tumors: a report from the Children's Cancer Group.

BACKGROUND: The International Neuroblastoma Pathology Classification (International Classification), which was established in 1999, is significant prognostically and is relevant biologically for the evaluation and analysis of patients with neuroblastic tumors (NTs). MYCN amplification is a known molecular marker for aggressive progression of NTs. These have been used together as important prognostic factors to define risk groups for patient stratification and protocol assignment. METHODS: A total of 628 NTs (535 neuroblastomas [NBs]); 21 ganglioneuroblastoma, intermixed [GNBi]; 9 ganglioneuromas [GN]; and 63 ganglioneuroblastoma, nodular [GNBn]) from the Children's Cancer Group studies were evaluated histologically (favorable histology [FH] tumors vs. unfavorable histology [UH] tumors) according to the International Classification and were tested molecularly for MYCN status (amplified vs. nonamplified). Four tumor subsets (FH-nonamplified, FH-amplified, UH-nonamplified, and UH-amplified) were defined by histopathology and MYCN status, and their prognostic effects were analyzed. Detailed analysis between morphologic indicators (grade of neuroblastic differentiation and mitosis-karyorrhexis index [MKI]) and MYCN status was done by using tumors in the NB category. RESULTS: There were 339 FH-nonamplified tumors (5-year event free survival [EFS], 92.1%); 8 FH-amplified tumors (EFS, 37.5%); 172 UH-nonamplified tumors (EFS, 40.9%); and 109 UH-amplified tumors (EFS, 15.0%). The prognostic effects on patients with tumors in the four subsets were independent from the factors of patient age and disease stage (P < 0.0001). MYCN amplification was seen almost exclusively in tumors of the NB category, and no patients with tumors in either the GNBi category or in the GN category and only two patients with tumors in the GNBn category had amplified MYCN. Among the patients with tumors in the NB category, patients with FH-nonamplified tumors (309 patients) had an excellent prognosis, and patients with UH-amplified tumors (107 patients) had the poorest clinical outcome in any age group. The prognosis for children with UH-nonamplified tumors (111 patients) was poor when they were diagnosed at age > 1.5 years. It was also noted that patients with UH-amplified tumors (median age, 2.14 years) were diagnosed at a significantly younger age compared with the patients with UH-nonamplified tumors (median age, 3.55 years). Histologically, MYCN-amplified tumors lacked neuroblastic differentiation regardless of the age of patients. MYCN amplification also was linked generally to increased mitotic and karyorrhectic activities. However, MKI classes in patients with MYCN-amplified tumors varied significantly, depending on the age at diagnosis, and younger patients had higher MKI classes. CONCLUSIONS: The combination of histopathologic evaluation and MYCN status distinguishes four clinical and biologic tumor subsets in patients with NTs. MYCN amplification seems to be the powerful driving force for preventing cellular differentiation regardless of patient age and for increasing mitotic and karyorrhectic activities in an age dependent manner.

Human NKT cells mediate antitumor cytotoxicity directly by recognizing target cell CD1d with bound ligand or indirectly by producing IL-2 to activate NK cells.

alpha-Galactosylceramide (alphaGalCer) stimulates NKT cells and has antitumor activity in mice. Murine NKT cells may directly kill tumor cells and induce NK cell cytotoxicity, but the mechanisms are not well defined. Newly developed human CD1d/alphaGalCer tetrameric complexes were used to obtain highly purified human alphaGalCer-reactive NKT cell lines (>99%), and the mechanisms of NKT cell cytotoxicity and activation of NK cells were investigated. Human NKT cells were cytotoxic against CD1d(-) neuroblastoma cells only when they were rendered CD1d(+) by transfection and pulsed with alphaGalCer. Four other CD1d(-) tumor cell lines of diverse origin were resistant to NKT cells, whereas Jurkat and U937 leukemia cell lines, which are constitutively CD1d(+), were killed. Killing of the latter was greatly augmented in the presence of alphaGalCer. Upon human CD1d/alphaGalCer recognition, NKT cells induced potent cytotoxicity of NK cells against CD1d(-) neuroblastoma cell lines that were not killed directly by NKT cells. NK cell activation depended upon NKT cell production of IL-2, and was enhanced by secretion of IFN-gamma. These data demonstrate that cytotoxicity of human NKT cells can be CD1d and ligand dependent, and that TCR-stimulated NKT cells produce IL-2 that is required to induce NK cell cytotoxicity. Thus, NKT cells can mediate potent antitumor activity both directly by targeting CD1d and indirectly by activating NK cells.

Ganglioside GM2/GD2 synthetase mRNA is a marker for detection of infrequent neuroblastoma cells in bone marrow.

GalNAcbeta1-4(NeuAcalpha2-3)Galbeta1-4Glcbeta1-Cer (GM2)/GalNAcbeta1-4(NeuAcalpha2-8NeuAcalpha2-3)Galbeta1-4Glcbeta1-1Cer (GD2) synthetase [beta-1,4-N-acetyl-galactosaminyl transferase (GalNAc-T)] mRNA, which encodes a key glycosyltransferase for ganglioside GD2 synthesis, was assessed as a molecular marker for detecting metastatic neuroblastoma cells in bone marrow (BM). GalNAc-T mRNA expression by neuroblastoma cell lines (n = 15), primary untreated neuroblastoma tumors (n = 29), morphologically normal BM (n = 22), peripheral blood stem cells (n = 10) from patients with cancers other than neuroblastoma, and blood mononuclear cells from normal donors (n = 17) was assessed by using reverse transcriptase-polymerase chain reaction (RT-PCR) and electrochemiluminescence detection assay (RT-PCR/ECL). BM harvested from 15 neuroblastoma patients was tested before and after ex vivo immunomagnetic bead purging, and results were compared to immunocytological analysis of the same specimens. All neuroblastoma cell lines (mean, 653 x 10(3) ECL units) and primary tumors (mean, 683 x 10(3) ECL units) were positive for significant expression of GalNAc-T mRNA compared to normal blood and BM cells. The RT-PCR/ECL assay could detect GalNAc-T mRNA in 100 pg of total RNA, and in a mixture of one neuroblastoma cell among 10(7) normal BM or blood cells. Eight of 15 autologous BM cells harvested from patients with neuroblastoma had tumor cells detectable by immunocytology, and all 15 were positive for GalNAc-T mRNA. After ex vivo purging, none of the BM cells was immunocytology-positive, but six remained positive by the RT-PCR/ECL assay. GalNAc-T mRNA provides a specific and sensitive molecular marker for RT-PCR/ECL detection of infrequent neuroblastoma cells in BM.

Allelic deletion at chromosome bands 11q14-23 is common in neuroblastoma.

BACKGROUND: Neuroblastoma tumorigenesis may involve the differential inactivation of multiple tumor suppressor genes. Recent data have suggested that a neuroblastoma suppressor gene may be located on the long arm of chromosome 11 (11q). PROCEDURE: We therefore analyzed 295 primary neuroblastomas from a representative group of patients for loss of heterozygosity (LOH) at 25 polymorphic markers spanning 11q. RESULTS: LOH was observed in 129 primary neuroblastomas (44%), and a common region of LOH mapped to 11q14-23. No correlation was found between 11q LOH and adverse prognostic variables, but a strong inverse relationship between 11q LOH and MYCN amplification (P < 0.001) was observed. There was no difference in overall survival when patients were stratified by 11q LOH status. However, 11q LOH was associated with a decreased overall survival probability when patients whose tumors had a single copy of MYCN were analyzed separately (P = 0.008). CONCLUSION: These data support the hypothesis that a tumor suppressor gene mapping within 11q14-23 is frequently inactivated during the malignant evolution of neuroblastoma.

Loss of heterozygosity for chromosome 14q in neuroblastoma.

BACKGROUND: Neuroblastoma is a genetically heterogeneous disease, with subsets of tumors demonstrating rearrangements of several genomic regions. Preliminary studies from several groups have identified loss of heterozygosity (LOH) for the long arm of chromosome 14 (14q) in 20-25% of primary neuroblastomas. PROCEDURE: To determine precisely the frequency and extent of 14q deletions, we performed LOH analysis for a large series of primary neuroblastomas using a panel of 11 highly polymorphic markers. RESULTS: LOH was detected in 83 of 372 tumors (22%). Although the majority of tumors with allelic loss demonstrated allelic loss for all informative markers, 13 cases showed LOH for only a portion of 14q. A single consensus region of deletion, which was shared by all tumors with 14q LOH, was defined within 14q23-q32 between D14S588 and the 14q telomere. Allelic loss for 14q was strongly correlated with the presence of 11q LOH (P < 0.001 ) and inversely correlated with MYCN amplification (P= 0.04). CONCLUSIONS: LOH for 14q was evident in all clinical risk groups, indicating that this abnormality may be a universal feature of neuroblastoma tumor development. These findings suggest that a tumor suppressor gene involved in the initiation or progression of neuroblastoma is located within distal 14q.

Comprehensive analysis of chromosome 1p deletions in neuroblastoma.

BACKGROUND: Chromosome 1p deletions are common in advanced neuroblastomas, but the biological and clinical implications of this clonal rearrangement remain controversial. Previous studies of chromosome 1p loss of heterozygosity (LOH) have been limited by analyses of relatively small number of tumors derived from heterogeneously assessed and treated patient populations. Therefore, a strictly representative cohort of 288 Children's Cancer Group neuroblastoma patients treated on the most recent phase III therapeutic trials was identified. PROCEDURE: Primary tumors from these patients were analyzed for LOH at precisely mapped and highly informative 1p polymorphic loci located from 1p32 to 1p36.3 by multiplex PCR. RESULTS: Ninety-three primary tumor specimens (32%) had LOH at multiple 1p36 marker loci. All 1p deletions overlapped the previously determined smallest region of overlap (SRO). One tumor had a small terminal deletion completely within 1p36.3, allowing for further refinement of the 1p36 SRO. We found no evidence to support an additional, nonoverlapping region of LOH within 1p32-36. We confirmed the strong correlation of 1p36 LOH with MYCN amplification (P < 0.001), advanced disease stage (P < 0.001), and decreased both 3-year event-free survival and overall survival probabilities (P< 0.001). When stratified for MYCN amplification status or entered into a multivariate analysis, 1p36 LOH remained predictive for decreased event-free survival, but not overall survival probability. CONCLUSIONS: These data support the hypothesis that inactivation of a tumor suppressor gene within 1p36.3 is associated with an increased risk for disease relapse.

Opsoclonus-myoclonus-ataxia syndrome in neuroblastoma: clinical outcome and antineuronal antibodies-a report from the Children's Cancer Group Study.

BACKGROUND: Opsoclonus-myoclonus-ataxia (OMA) is a paraneoplastic neurologic syndrome affecting 2-3% of children with neuroblastoma. Although children with OMA and neuroblastoma may have higher survival, many experience a significant amount of late neurologic impairment, which may be immunologically mediated. The aim of this study was to compare the outcome of neuroblastoma patients with and without OMA, relating to prognostic factors, treatment, and the presence or absence of anti-neuronal antibodies. PROCEDURE: Questionnaires were mailed out requesting information on the current neurologic status of patients who submitted sera at diagnosis to the Children's Cancer Group serum bank from 1980 to 1994. Information was requested on clinical and biological patient characteristics as well as clinical aspects of the patients identified as having OMA syndrome, including presentation and treatment for OMA, late sequelae of OMA, the presence or absence of antineuronal antibodies, and survival. Sera from 16 of the OMA patients and 48 case-controls with neuroblastoma were assayed for anti-neuronal antibodies. RESULTS: Of the 675 responses received, 21 patients had OMA. Ninety percent of OMA patients presented with non-metastatic disease, vs. 35% of non-OMA patients. Estimated 3-year survival for the OMA patients with nonmetastatic disease (stage I, II, III) greater than 1 year of age was 100% vs. 77% for similar non-OMA patients (P = 0.0222). At follow-up, 14/19 evaluable OMA patients displayed some form of developmental or neurologic abnormality. There was no significant correlation of late sequelae with antineuronal antibodies, age, time between OMA symptoms and diagnosis, or treatment given for tumor or OMA. There was a significant correlation of late sequelae with lower stage disease (I and II) compared to more advanced disease (III and IV). CONCLUSIONS: Patients with OMA and neuroblastoma have excellent survival but a high risk of neurologic sequelae. Favorable disease stage correlates with a higher risk for development of neurologic sequelae. The role of anti-neuronal antibodies in late sequelae of OMA needs further clarification.

Opsoclonus-myoclonus-ataxia syndrome in neuroblastoma: histopathologic features-a report from the Children's Cancer Group.

BACKGROUND: Opsoclonus-myoclonus-ataxia (OMA) is a paraneoplastic syndrome that occurs in about 2-3% of all cases of neuroblastoma. The histopathologic characteristics of neuroblastoma tumors associated with this syndrome were evaluated in a series of cases and controls. PROCEDURE: Pathology slides from a total of 54 neuroblastoma tumors were reviewed blindly. They included 13 tumors associated with opsoclonus-myoclonus and 41 age- and stage-matched controls. All tumors were classified into either the favorable (FH) or unfavorable histology (UH) group according to the International Neuroblastoma Pathology Classification (the Shimada system). Grade of lymphocytic infiltration was evaluated and presence or absence of lymphoid follicles was recorded in the individual tumor tissues. RESULTS: Twelve of 13 cases with opsoclonus-myoclonus were in the FH group. Twelve of 13 cases had diffuse (found in every section prepared from the multiple portions of the primary tumor) and extensive (occupying more than 50% of a single of multiple microscopic fields with x 100 magnification) lymphocytic infiltration with lymphoid follicles. Of the 41 control cases (27 FH and 14 UH tumors), 18 had focal areas of lymphocytic infiltration and six showed lymphoid follicles, but none had diffuse or extensive infiltration in their primary tumors. CONCLUSIONS: Diffuse and extensive lymphocytic infiltration with lymphoid follicles is a characteristic histologic feature of neuroblastic tumors with opsoclonus-myoclonus. This observation suggests an immune-mediated mechanism for this rare paraneoplastic syndrome.

Homozygous deletion of CDKN2A (p16INK4a/p14ARF) but not within 1p36 or at other tumor suppressor loci in neuroblastoma.

Loss of heterozygosity of several specific genomic regions is frequently observed in neuroblastoma tumors and cell lines, but homozygous deletion (HD) is rare, and no neuroblastoma tumor suppressor gene (TSG) has yet been identified. We performed a systematic search for HD, indicative of a disrupted TSG, in a panel of 46 neuroblastoma cell lines. An initial search focused on a well-characterized consensus region of hemizygous deletion at 1p36.3, which occurs in 35% of primary neuroblastomas. Each cell line was screened with 162 1p36 markers, for a resolution of 13 kb within the consensus 1p36.3 deletion region and 350 kb throughout the remainder of 1p36. No HDs were detected. This approach was expanded to survey 21 known TSGs, specifically targeting intragenic regions frequently inactivated in other malignancies. HD was detected only at the CDKN2A (p16INK4a/p14ARF) gene at 9p21 and was observed in 4 of 46 cell lines. The observed region of HD included all exons of both CDKN2A and the closely linked CDKN2B (p15INK4b) gene for cell lines LA-N-6 and CHLA-174, all exons of CDKN2A but none of CDKN2B for CHLA-179, and only 104 bp within CDKN2A exon 2 for CHLA-101. All four deletions are predicted to inactivate the coding regions of both p16INK4a and p14ARF. HD was observed in corresponding primary tumor samples for CHLA-101 and CHLA-174 but was not present in constitutional samples. These results suggest that for neuroblastoma, large HDs do not occur within 1p36, most known TSGs are not homozygously deleted, and biallelic inactivation of CDKN2A may contribute to tumorigenicity in a subset of cases.

Residential pesticide exposure and neuroblastoma.

Neuroblastoma is the most common neoplasm in children under 1 year of age. We examined the relation between residential exposure to pesticides and neuroblastoma, using data from a case-control study of risk factors for neuroblastoma. Incident cases of neuroblastoma (N = 538) were identified through the Pediatric Oncology Group and the Children's Cancer Group. One age-matched control was identified for each case by random digit dialing. Telephone interviews with each parent collected information on residential exposure to pesticides. Pesticide use in both the home and garden were modestly associated with neuroblastoma [odds ratio (OR) = 1.6 (95% confidence interval [95% CI] = 1.0-2.3, and OR = 1.7 (95% CI = 0.9-2.1), respectively]. Compared with infants [OR = 1.0 (95% CI = 0.6-2.0)], stronger associations were found for garden pesticides in children diagnosed after 1 year of age [OR = 2.2 (95% CI = 1.3-3.6)], which suggests that pesticides may act through a mechanism more common for neuroblastomas in older children. There was no evidence of differential pesticide effects in subgroups of neuroblastoma defined by MYCN oncogene amplification or tumor stage.