Outcomes of patients with bilateral retinoblastoma: A report from the RIVERBOAT Consortium

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Background: Retinoblastoma (RB) is the most common tumor of the eye in childhood. Intraocular RB cure rates approach 100%. Therefore, treatment advances have focused on globe salvage preserving functional vision. The Research Into Visual Endpoints and RB Health Outcomes After Treatment (RIVERBOAT) consortium was established to examine patient health outcomes, including vision, in the contemporary therapy era. Methods: Patients with RB treated at consortium centers from 2007 to the present were identified. Medical record abstraction was performed for disease presentation, treatment, and outcomes. A subset of the patients returned to centers and completed functional vision questionnaires (Child Vision Function Questionnaire for ages 0 – 7 and Cardiff Visual Ability Questionnaire for Children for ages >8) and had visual acuity assessed. For participants who could not yet return for a study evaluation, medical record abstraction alone was performed. Results: Among 463 participants enrolled to date, 193 (42%) had bilateral disease. Two each had metastatic RB, trilateral RB, and secondary osteosarcoma. One patient each with metastatic RB and trilateral RB is deceased, with overall survival for the cohort of 99%. The eye group distribution (International Intraocular Retinoblastoma Classification) was 14% A, 22% B, 14% C, 28% D, 19% E and 3% not classified. Primary enucleation was performed in 43 (22%), secondary enucleation in 48 (25%) and bilateral enucleation in 1(0.5%). Intravenous chemotherapy (IV) alone was administered in 58%, intra-arterial chemotherapy (IAC) alone in 4%, with 31% receiving both. Among 145 patients who did not require secondary or bilateral enucleation, the distribution was 16% A, 21% B, 16% C, 28% D, 15% E, and 4% non-classified eyes. This salvage was achieved with IV alone, IAC alone, or both in 55%, 5% and 30% respectively and with ophthalmic therapy only in 10%. The mean percentage of patients receiving IAC per year increased from 6% in 2008 – 2013 to 11% in 2014 – 2022 and was stable at 11% in 2018 – 2022. Among 53 patients who have reported functional vision to date, the mean scores were 0.81 for < 3 years 0.80 for 3-7 years and -1.31 for those >8 years, all considered to be good functional vision. Among 50 eyes in 37 of these 53 patients, 33 had normal vision (20/20-20/40) across A to E groups. Moderate vision loss (> 20/40 – 20/70) was noted in 1 C and 1 B eye and low vision (> 20/70 - < 20/200) in 6 group B, C or D eyes. Nine B or D eyes were legally blind (>20/200). No patients had two legally blind eyes. Conclusions: In this cohort of RB patients with bilateral disease treated between 2007 and 2022, 52% have been successfully treated without enucleation. Self-reported functional vision in 53 of these patients with all group eyes was good. Only 6 of 50 eyes in 37 patients met criteria for legal blindness and 66% of eyes had normal vision. With cohort accrual ongoing, we will determine if these promising outcomes continue.

Outcomes of patients with unilateral retinoblastoma: A report from the RIVERBOAT Consortium

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Background: Retinoblastoma (RB) is the most common tumor of the eye in childhood. Intraocular RB cure rates approach 100%. Therefore, treatment now focuses on globe salvage preserving functional vision. The Research Into Visual Endpoints and RB Health Outcomes After Treatment (RIVERBOAT) consortium was established to examine patient health outcomes, including vision, in the contemporary therapy era. Methods: Patients with RB treated at consortium centers from 2007 to present were identified. Medical record abstraction was performed for disease presentation, treatment, and outcomes. A subset of the patients returned to centers and completed functional vision questionnaires (Child Vision Function Questionnaire - ages 0 – 7 and Cardiff Visual Ability Questionnaire for Children - ages > 8) and had visual acuity assessed. For participants who could not yet return for a study evaluation, medical record abstraction alone was performed. Results: Among 463 participants enrolled to date, 270 (58%) had unilateral disease. One patient with metastatic RB did not survive, resulting in overall survival of 99.6. There was one case of secondary leukemia. The eye group distribution (International Intraocular Retinoblastoma Classification) was 0.4% A, 5.6% B, 7.0% C, 36.0% D, 49.0% E and 2.0% not classified. 131 (49%) patients underwent primary enucleation and are not included in further analyses. Among the remaining 139 patients, 3% were treated with local ophthalmic therapy only, 22% with intravenous chemotherapy (IV) only, 53% with intra-arterial chemotherapy (IAC) only, 22% with IV and IAC, and 35% required secondary enucleation. Globe salvage after chemotherapy was successful in 100% A, 93% B, 82% C, 72% D, and 48% E eyes. This salvage was achieved with IV only, IAC only, or both in 22%, 58% and 20% respectively. The mean percentage of patients receiving IAC per year increased from 13% (2008 – 2013) to 21% (2014 – 2017) to 28% (2018 – 2022). In 29 patients without enucleation who reported functional vision to date, the mean scores (survey theoretical ranges) were 0.72 for < 3 years (0.57 to 0.87), 0.82 for 3 -7 years (0.56 to 0.94) and -2.72 for > 8 years (-2.53 to -0.51), all considered good functional vision. In 20 of these 29 patients, 4 eyes had normal vision (20/20-20/40) across A to D groups. Moderate vision loss (> 20/40 – 20/70) was noted in 3 D eyes and low vision (> 20/70 - < 20/200) in 1 D eye. Twelve B through E eyes met criteria for a legally blind eye (>20/200). Conclusions: In this cohort of RB patients with unilateral disease treated from 2007 - 2022, 66% required primary or secondary enucleation. Among 29 patients with globe salvage, self-reported functional vision was good, but 12 eyes in 20 of the patients were legally blind. IAC only or IV plus IAC was most used in those who avoided secondary enucleation. With ongoing cohort accrual and increased IAC use, it will remain to be determined if globe salvage with functional vision will improve.

Structural Properties of Inverted Hexagonal Phase: A Hybrid Computational and Experimental Approach

Inverted/reverse hexagonal (H_II) phases are of special interest in several fields of research, including nanomedicine. We used molecular dynamics (MD) simulation to study H_II systems composed of dioleoylphosphatidylethanolamine (DOPE) and palmitoyloleoylphosphatidylethanolamine (POPE) at several hydration levels and temperatures. The effect of the hydration level on several H_II structural parameters, including deuterium order parameters, was investigated. We further used MD simulations to estimate the maximum hydrations of DOPE and POPE H_II lattices at several given temperatures. Finally, the effect of acyl chain unsaturation degree on the H_II structure was studied via comparing the DOPE with POPE H_II systems. In addition to MD simulations, we used deuterium nuclear magnetic resonance (²H NMR) and small-angle X-ray scattering (SAXS) experiments to measure the DOPE acyl chain order parameters, lattice plane distances, and the water core radius in H_II phase DOPE samples at several temperatures in the presence of excess water. Structural parameters calculated from MD simulations are in excellent agreement with the experimental data. Dehydration decreases the radius of the water core. An increase in hydration level slightly increased the deuterium order parameter of lipids acyl chains, whereas an increase in temperature decreased it. Lipid cylinders undulated along the cylinder axis as a function of hydration level. The maximum hydration levels of PE H_II phases at different temperatures were successfully predicted by MD simulations based on a single experimental measurement for the lattice plane distance in the presence of excess water. An increase in temperature decreases the maximum hydration and consequently the radius of the water core and lattice plane distances. Finally, DOPE formed H_II structures with a higher curvature compared to POPE, as expected. We propose a general protocol for constructing computational H_II systems that correspond to the experimental systems. This protocol could be used to study H_II systems composed of molecules other than the PE systems used here and to improve and validate force field parameters by using the target data in the H_II phase.

Maintaining Outstanding Outcomes Using Response- and Biology-Based Therapy for Intermediate-Risk Neuroblastoma: A Report From the Children's Oncology Group Study ANBL0531

PURPOSE

The primary objective of the Children's Oncology Group study ANBL0531 (ClinicalTrials.gov identifier: NCT00499616) was to reduce therapy for subsets of patients with intermediate-risk neuroblastoma using a biology- and response-based algorithm to assign treatment duration while maintaining a 3-year overall survival (OS) of 95% or more for the entire cohort.

PATIENTS AND METHODS

Children younger than age 12 years with intermediate-risk stage 2A/2B or stage 3 tumors with favorable histology; infants younger than age 365 days with stage 3, 4 or 4S disease; and toddlers from 365 to younger than 547 days with favorable histology, hyperdiploid stage 4, or unfavorable histology stage 3 tumors were eligible. Patients with MYCN-amplified tumors were excluded. Patients were assigned to initially receive two (group 2), four (group 3), or eight (group 4) cycles of chemotherapy with or without surgery on the basis of prognostic markers, including allelic status of chromosomes 1p and 11q; ultimate duration of therapy was determined by overall response.

RESULTS

Between 2007 and 2011, 404 evaluable patients were enrolled. Compared with legacy Children's Oncology Group studies, subsets of patients had a reduction in treatment. The 3-year event-free survival and OS rates were 83.2% (95% CI, 79.4% to 87.0%) and 94.9% (95% CI, 92.7% to 97.2%), respectively. Infants with stage 4 tumors with favorable biology (n = 61) had superior 3-year event-free survival compared with patients with one or more unfavorable biologic features (n = 47; 86.9% [95% CI, 78.3% to 95.4%] v 66.8% [95% CI, 53.1% to 80.6%]; P = .02), with a trend toward OS advantage (95.0% [95% CI, 89.5% to 100%] v 86.7% [95% CI, 76.6% to 96.7%], respectively; P = .08). OS for patients with localized disease was 100%.

CONCLUSION

Excellent survival was achieved with this treatment algorithm, with reduction of therapy for subsets of patients. More-effective treatment strategies still are needed for infants with unfavorable biology stage 4 disease.

Ionizable amino lipid interactions with POPC: implications for lipid nanoparticle function

Lipid nanoparticles (LNPs) composed of ionizable cationic lipids are currently the leading systems for siRNA delivery in liver disease, with the major limitation of low siRNA release efficacy into the cytoplasm. Ionizable cationic lipids are known to be of critical importance in LNP structure and stability, siRNA entrapment, and endosomal disruption. However, their distribution inside the LNPs and their exact role in cytoplasmic delivery remain unclear. A recent study [Kulkarni et al., On the formation and morphology of lipid nanoparticles containing ionizable cationic lipids and siRNA, ACS Nano, 2018, 12(5), 4787-4795] on LNP-siRNA systems containing the ionizable lipid DLin-KC2-DMA (also known as KC2 with an apparent pKa of ca. 6.7) suggested that neutral KC2 segregates from other components and forms an amorphous oil droplet in the core of LNPs. In this paper, we present evidence supporting the model proposed by Kulkarni et al. We studied KC2 segregation in the presence of POPC using molecular dynamics simulation, deuterium NMR, SAXS, and cryo-TEM experiments, and found that neutral KC2 has a high tendency to separate from POPC dispersions. KC2 confinement, upon raising the pH during the formulation process, could result in rearrangement of the internal structure of LNPs. As interactions between cationic KC2 and anionic endosomal lipids are thought to be a key factor in cargo release, KC2 confinement inside the LNP may be responsible for the observed low release efficacy.

AGRICULTURAL BEST MANAGEMENT PRACTICE SENSITIVITY TO CHANGING AIR TEMPERATURE AND PRECIPITATION

Agricultural best management practices (BMPs) reduce non-point source pollution from cropland. Goals for BMP adoption and expected pollutant load reductions are often specified in water quality management plans to protect and restore waterbodies; however, estimates of needed load reductions and pollutant removal performance of BMPs are generally based on historic climate. Increasing air temperatures and changes in precipitation patterns and intensity are anticipated throughout the U.S. over the 21st century. The effects of such changes on agricultural pollutant loads have been addressed by several authors, but how these changes will affect the performance of widely promoted BMPs has received limited attention. We use the Soil and Water Assessment Tool (SWAT) to investigate potential changes in the effectiveness of conservation tillage, no-till, vegetated filter strips, grassed waterways, nutrient management, winter cover crops, and drainage water management practices under potential future temperature and precipitation patterns. We simulate two agricultural watersheds in the Minnesota Corn Belt and the Georgia Coastal Plain with different hydro-climatic settings, under recent conditions (1950-2005) and multiple potential future mid-century (2030-2059) and late-century (2070-2099) climate scenarios. Results suggest future increases in agricultural source loads of sediment, nitrogen and phosphorous. Most BMPs continue to reduce loads, but removal efficiencies generally decline due to more intense runoff events, biological responses to changes in soil moisture and temperature, and exacerbated upland loading. The coupled effects of higher upland loading and reduced BMP efficiencies suggest that wider adoption, resizing, and/or combining practices may be needed in the future to meet water quality goals for agricultural lands.

Defining Risk Factors for Chemotherapeutic Intervention in Infants With Stage 4S Neuroblastoma: A Report From Children's Oncology Group Study ANBL0531

PURPOSE

Infants with stage 4S neuroblastoma usually have favorable outcomes with observation or minimal chemotherapy. However, young infants with symptoms secondary to massive hepatomegaly or with unfavorable tumor biology are at high risk of death. Our aim was to improve outcomes for patients with symptomatic and/or unfavorable biology 4S neuroblastoma with a uniform treatment approach using a biology- and response-based algorithm.

PATIENTS AND METHODS

The subset of patients with 4S disease with MYCN-not amplified tumors with impaired or impending organ dysfunction, or with unfavorable histology and/or diploid DNA index, were eligible. Patients were assigned to receive two, four, or eight cycles of chemotherapy on the basis of histology, diploid DNA index, chromosome arm 1p or 11q loss of heterozygosity (LOH) status, and symptoms.

RESULTS

Forty-nine eligible patients were enrolled: 41 were symptomatic and 28 had unfavorable biology. Seventeen patients (symptomatic, favorable biology) were assigned two cycles, 21 patients (any unfavorable biologic feature without 1p or 11q LOH) were assigned four cycles, and 11 patients (unfavorable biology including 1p and/or 11q LOH [n = 7] or symptomatic with unknown biology [n = 4]), were assigned eight cycles. The 3-year overall survival was 81.4% ± 5.8%. Eight of nine deaths were in patients younger than 2 months of age at diagnosis (median, 9 days [range, 1 to 68 days]): five acute deaths were a result of hepatomegaly and associated toxicities; two were a result of late relapse in patients with unfavorable biology; and two were a result of treatment complications. No deaths occurred after protocol-mandated pre-emptive treatment of infants younger than 2 months with hepatomegaly, regardless of symptoms. A new scoring algorithm for emergent chemotherapy in patients with 4S disease was developed on the basis of this experience.

CONCLUSION

The outcome for 4S neuroblastoma can be improved with pre-emptive chemotherapy for evolving hepatomegaly or other baseline comorbidities in infants younger than 2 months of age.

Exploring intentions of physician-scientist trainees: factors influencing MD and MD/PhD interest in research careers

BACKGROUND

Prior studies have described the career paths of physician-scientist candidates after graduation, but the factors that influence career choices at the candidate stage remain unclear. Additionally, previous work has focused on MD/PhDs, despite many physician-scientists being MDs. This study sought to identify career sector intentions, important factors in career selection, and experienced and predicted obstacles to career success that influence the career choices of MD candidates, MD candidates with research-intense career intentions (MD-RI), and MD/PhD candidates.

METHODS

A 70-question survey was administered to students at 5 academic medical centers with Medical Scientist Training Programs (MSTPs) and Clinical and Translational Science Awards (CTSA) from the NIH. Data were analyzed using bivariate or multivariate analyses.

RESULTS

More MD/PhD and MD-RI candidates anticipated or had experienced obstacles related to balancing academic and family responsibilities and to balancing clinical, research, and education responsibilities, whereas more MD candidates indicated experienced and predicted obstacles related to loan repayment. MD/PhD candidates expressed higher interest in basic and translational research compared to MD-RI candidates, who indicated more interest in clinical research. Overall, MD-RI candidates displayed a profile distinct from both MD/PhD and MD candidates.

CONCLUSIONS

MD/PhD and MD-RI candidates experience obstacles that influence their intentions to pursue academic medical careers from the earliest training stage, obstacles which differ from those of their MD peers. The differences between the aspirations of and challenges facing MD, MD-RI and MD/PhD candidates present opportunities for training programs to target curricula and support services to ensure the career development of successful physician-scientists.

Gas-phase fragmentations of N-methylimidazolidin-4-one organocatalysts

N-methylimidazolidin-4-one organocatalysts were studied in the gas phase. Protonated and sodium-cationized (sodiated) molecules are conveniently accessible by electrospray mass spectrometry. Protonation enables three different closed-shell paths of ring cleavage leading to iminium ions. The fragmentation pattern is largely unaffected by exocyclic substituents and thus is valuable to characterize the substance type as N-methylimidazolidin-4-ones. Sodiated species show a distinctly different fragmentation that is less useful for characterization purposes: apart from signal loss due to dissociation of Na⁺ , the observation of benzyl radical loss is by far predominant. Only in absence of a benzyl substituent, an analogue of the third ring cleavage (loss of [C₂ H₅ NO]) is observed. Copyright © 2017 John Wiley & Sons, Ltd.

A porcine model system of BRCA1 driven breast cancer

BRCA1 is a breast and ovarian tumor suppressor. Hereditary mutations in BRCA1 result in a predisposition to breast cancer, and BRCA1 expression is down-regulated in ~30% of sporadic cases. The function of BRCA1 remains poorly understood, but it appears to play an important role in DNA repair and the maintenance of genetic stability. Mouse models of BRCA1 deficiency have been developed in an attempt to understand the role of the gene in vivo. However, the subtle nature of BRCA1 function and the well-known discrepancies between human and murine breast cancer biology and genetics may limit the utility of mouse systems in defining the function of BRCA1 in cancer and validating the development of novel therapeutics for breast cancer. In contrast to mice, pig biological systems, and cancer genetics appear to more closely resemble their human counterparts. To determine if BRCA1 inactivation in pig cells promotes their transformation and may serve as a model for the human disease, we developed an immortalized porcine breast cell line and stably inactivated BRCA1 using miRNA. The cell line developed characteristics of breast cancer stem cells and exhibited a transformed phenotype. These results validate the concept of using pigs as a model to study BRCA1 defects in breast cancer and establish the first porcine breast tumor cell line.

Health behaviors of minority childhood cancer survivors

BACKGROUND

Available data have suggested that childhood cancer survivors (CCSs) are comparable to the general population with regard to many lifestyle parameters. However, to the authors' knowledge, little is known regarding minority CCSs. This cross-sectional study describes and compares the body mass index and health behaviors of African American, Hispanic, and white survivors with each other and with noncancer controls.

METHODS

Participants included 452 adult CCSs (150 African American, 152 Hispanic, and 150 white individuals) recruited through 4 childhood cancer treating institutions and 375 ethnically matched noncancer controls (125 in each racial/ethnic group) recruited via targeted digit dial. All participants completed a 2-hour in-person interview.

RESULTS

Survivors and noncancer controls reported similar health behaviors. Within survivors, smoking and physical activity were found to be similar across racial/ethnic groups. African American and Hispanic survivors reported lower daily alcohol use compared with white individuals, but consumed unhealthy diets and were more likely to be obese.

CONCLUSIONS

This unique study highlights that many minority CCSs exhibit lifestyle profiles that contribute to an increased risk of chronic diseases and late effects. Recommendations for behavior changes must consider the social and cultural context in which minority survivors may live.

A unique description of stage IV extranodal marginal zone lymphoma (EMZL) in an adolescent associated with gamma heavy chain disease

Extranodal Marginal zone lymphoma (EMZL) is a rare, usually localized disease in children. Advanced stage EMZL in adults is considered incurable, with prolonged remissions after chemotherapy. Gamma heavy chain disease (γHCD) is a rare disease of adults associated with lympho-proliferative processes with no comparable reports in children. A case of stage-IV EMZL with γHCD in an adolescent is discussed including treatment with Bendamustine plus Rituximab. The patient remains disease free 18 months from diagnosis. This case highlights necessity for careful diagnostic work-up to identify indolent lymphomas in children which may respond to less toxic chemotherapy than used for common pediatric lymphomas.

Electronic Personal Health Records for Childhood Cancer Survivors: An Exploratory Study

Purpose: Childhood cancer survivors have complex healthcare needs that may be effectively communicated using electronic personal health records. This study explores the knowledge, interest, and attitudes of a sample of survivors and some of their caregivers towards electronic personal health records (ePHRs). Methods: This descriptive study was conducted in a pediatric hematology-oncology clinic and associated survivorship clinic with a convenience sample of caregivers of survivors who were <14 years old and survivors ≥14 years old along with their caregivers when present. A semi-structured interview was conducted with survivors and some caregivers to understand their knowledge, interest, and attitudes towards adoption of ePHRs. Results: Interviews were completed with 11 caregivers of young survivors, four survivors alone, and five survivor-caregiver dyads. Survivors ranged in age at diagnosis from 1 to 17 years old. Among the ethnically diverse sample, approximately half of the nine survivors and 25% of 16 caregivers reported having some knowledge of ePHRs. Eighty-nine percent (8/9) of the survivors and 81% (13/16) of the caregivers reported that they were somewhat or very comfortable using the internet. All nine survivors and 75% of caregivers were interested in the adoption of ePHRs. Data security and privacy were the primary concerns expressed. Conclusions: Interest in adoption of ePHRs to manage cancer survivorship-related health information was high. Most felt that the privacy and security concerns would not prevent adoption. Additional research is needed on larger and more representative samples of survivors to understand what types of support and education are needed to effectively implement ePHRs.

Ototoxicity in children with high-risk neuroblastoma: prevalence, risk factors, and concordance of grading scales--a report from the Children's Oncology Group

PURPOSE

Platinum-based therapy is the mainstay for management of high-risk neuroblastoma. Prevalence of platinum-related ototoxicity has ranged from 13% to 95% in previous reports; variability is attributable to small samples and disparate grading scales. There is no consensus regarding optimal ototoxicity grading. Furthermore, prevalence and predictors of hearing loss in a large uniformly treated high-risk neuroblastoma population are unknown. We address these gaps in our study.

PATIENTS AND METHODS

Audiologic testing was completed after administration of cisplatin alone (< 400 mg/m(2); exposure one) or after cisplatin (400 mg/m(2)) plus carboplatin (1,700 mg/m(2); exposure two). Hearing loss was graded using four scales (American Speech-Language-Hearing Association; Brock; Chang; and Common Terminology Criteria for Adverse Events, version 3 [CTCAEv3]).

RESULTS

Of 489 eligible patients, 333 had evaluable audiologic data. Median age at diagnosis was 3.3 years. Prevalence of severe hearing loss differed by scale. For those in the exposure-one group, prevalence ranged from 8% per Brock to 47% per CTCAEv3 (Brock v CTCAEv3 and Chang, P < .01; CTCAEv3 v Chang, P = .16); for those in the exposure-two group, prevalence ranged from 30% per Brock to 71% per CTCAEv3 (all pair-wise comparisons, P < .01). In patients requiring hearing aids, hearing loss was graded as severe in 49% (Brock), 91% (Chang), and 100% (CTCAEv3). Risk factors for severe hearing loss included exposure to cisplatin and carboplatin compared with cisplatin alone and hospitalization for infection.

CONCLUSION

Severe hearing loss is prevalent among children with high-risk neuroblastoma. Exposure to cisplatin combined with myeloablative carboplatin significantly increases risk. The Brock scale underestimates severe hearing loss and should be used with caution in this setting.

Outcome analysis of non-high-risk neuroblastoma patients enrolled on Children’s Oncology Group trials P9641 and A3961

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Background: Patients with non-high-risk neuroblastoma (low- and intermediate-risk) generally have an excellent event free (EFS) and overall (OS) survival with current therapy. However, within this heterogeneous patient population, there are patients that may benefit from further therapy reduction and patients that may benefit from augmented therapy. Methods: Survival tree regression analysis was performed in patients enrolled on P9641 and A3961 with OS the primary endpoint. Univariate Cox proportional hazards models determined statistically significant prognostic factors. Secondary analysis of cases with MYCN non-amplified, non-high-risk neuroblastoma classified patients by age, INSS stage, Shimada histology and genomic features to determine 5-year EFS and OS. Favorable genomics were defined as hyperdiploid tumors without 1p or 11q loss of heterozygosity (LOH). Those with LOH at 1p or 11q or with a diploid DNA index were considered unfavorable. Patients without genomic data were excluded. Results: In the survival tree analysis, ploidy and genomic features were found to be statistically significant. In the secondary analysis, patients <18 months of age with stage 2 or 3, favorable histology tumors with favorable genomic profile had 5-year EFS and OS rates of 92.9±3.9% and 100% respectively. Patients with stage 2 and 3 tumors, unfavorable histology and unfavorable genomic features had EFS of 68.4±8.0% and OS of 78.4±7.0%. Patients <12 months of age with stage 4 disease and either unfavorable histologic or genomic features had EFS of 69.1±5.4% and OS of 88.5±3.8%. Conclusions: Excellent outcomes in non-high-risk neuroblastoma patients with favorable histologic and genomic features suggest further reduction in therapy is possible in this cohort while maintaining survival and decreasing side effects. Select patients with unfavorable features have suboptimal OS and would benefit from modifications in therapy. Histologic and genomic criteria can be used to identify patients with non-high-risk neuroblastoma that may benefit from modifications in therapy. These data support the conduct of a cooperative group clinical trial to refine therapy for patients with non-high-risk disease.

Outcome after surgery alone or with restricted use of chemotherapy for patients with low-risk neuroblastoma: results of Children's Oncology Group study P9641

PURPOSE

The primary objective of Children's Oncology Group study P9641 was to demonstrate that surgery alone would achieve 3-year overall survival (OS) ≥ 95% for patients with asymptomatic International Neuroblastoma Staging System stages 2a and 2b neuroblastoma (NBL). Secondary objectives focused on other low-risk patients with NBL and on those who required chemotherapy according to protocol-defined criteria.

PATIENTS AND METHODS

Patients underwent maximally safe resection of tumor. Chemotherapy was reserved for patients with, or at risk for, symptomatic disease, with less than 50% tumor resection at diagnosis, or with unresectable progressive disease after surgery alone.

RESULTS

For all 915 eligible patients, 5-year event-free survival (EFS) and OS were 89% ± 1% and 97% ± 1%, respectively. For patients with asymptomatic stage 2a or 2b disease, 5-year EFS and OS were 87% ± 2% and 96% ± 1%, respectively. Among patients with stage 2b disease, EFS and OS were significantly lower for those with unfavorable histology or diploid tumors, and OS was significantly lower for those ≥ 18 months old. For patients with stage 1 and 4s NBL, 5-year OS rates were 99% ± 1% and 91% ± 1%, respectively. Patients who required chemotherapy at diagnosis achieved 5-year OS of 98% ± 1%. Of all patients observed after surgery, 11.1% experienced recurrence or progression of disease.

CONCLUSION

Excellent survival rates can be achieved in asymptomatic low-risk patients with stages 2a and 2b NBL after surgery alone. Immediate use of chemotherapy may be restricted to a minority of patients with low-risk NBL. Patients with stage 2b disease who are older or have diploid or unfavorable histology tumors fare less well. Future studies will seek to refine risk classification.

Prognostic value of the stage 4S metastatic pattern and tumor biology in patients with metastatic neuroblastoma diagnosed between birth and 18 months of age

PURPOSE

Patients with neuroblastoma younger than 12 months of age with a 4S pattern of disease (metastases limited to liver, skin, bone marrow) have better outcomes than infants with stage 4 disease. The new International Neuroblastoma Risk Group (INRG) staging system extends age to 18 months for the 4S pattern. Our aim was to determine which prognostic features could be used for optimal risk classification among patients younger than 18 months with metastatic disease.

METHODS

Event-free survival (EFS) and overall survival were analyzed by log-rank tests, Cox models, and survival tree regression for 656 infants with stage 4S neuroblastoma younger than 12 months of age and 1,019 patients with stage 4 disease younger than 18 months of age in the INRG database.

RESULTS

Unfavorable biologic features were more frequent in infants with stage 4 disease than in infants with 4S tumors and higher overall in those age 12 to 18 months (although not different for stage 4 v 4S pattern). EFS was significantly better for infants younger than 12 months with 4S pattern than with stage 4 disease (P < .01) but similar for toddlers age 12 to 18 months with stage 4 versus 4S pattern. Among 717 patients with stage 4S pattern, patients age 12 to 18 months had worse EFS than those age younger than 12 months (P < .01). MYCN, 11q, mitosis-karyorrhexis index (MKI), ploidy, and lactate dehydrogenase were independently statistically significant predictors of EFS and more highly predictive than age or metastatic pattern. MYCN, 11q, MKI, histology, and 1p were combined in a survival tree for improved risk stratification.

CONCLUSION

Tumor biology is more critical than age or metastatic pattern for prognosis of patients age younger than 18 months with metastatic neuroblastoma and should be considered for risk stratification.

Medical radiation exposure and risk of retinoblastoma resulting from new germline RB1 mutation

Although ionizing radiation induces germline mutations in animals, human studies of radiation-exposed populations have not detected an effect. We conducted a case-control study of sporadic bilateral retinoblastoma, which results from a new germline RB1 mutation, to investigate gonadal radiation exposure of parents from medical sources before their child's conception. Parents of 206 cases from nine North American institutions and 269 controls participated; fathers of 184 cases and 223 friend and relative controls and mothers of 204 cases and 260 controls provided information in telephone interviews on their medical radiation exposure. Cases provided DNA for RB1 mutation testing. Of common procedures, lower gastrointestinal (GI) series conferred the highest estimated dose to testes and ovaries. Paternal history of lower GI series was associated with increased risk of retinoblastoma in the child [matched odds ratio (OR) = 3.6, 95% confidence interval (CI) = 1.2-11.2, two-sided p = 0.02], as was estimated total testicular dose from all procedures combined (OR for highest dose=3.9, 95% CI = 1.2-14.4, p = 0.02). Maternal history of lower GI series was also associated with increased risk (OR = 7.6, 95% CI = 2.8-20.7, p < 0.001) as was the estimated total dose (OR for highest dose = 3.0, 95% CI = 1.4-7.0, p = 0.005). The RB1 mutation spectrum in cases of exposed parents did not differ from that of other cases. Some animal and human data support our findings of an association of gonadal radiation exposure in men and women with new germline RB1 mutation detectable in their children, although bias, confounding, and/or chance may also explain the results.

Conjunctival marginal zone b-cell lymphoma in a 13-year-old child

Ocular adnexal lymphoma is a hematopoietic tumor that arises in the conjunctiva, orbit, eyelid, lacrimal gland, or lacrimal sac. The treatment options in children have not been addressed in the literature. The authors describe a 13-year-old child with ocular adnexal lymphoma and discuss the treatment options.

Prolonged chronic phase of greater than 10 years of chronic myelogenous leukemia in a patient with congenital human immunodefeciency virus infection

A 15-year-old male with congenital HIV infection was diagnosed with chronic myelogenous leukemia (CML) at age 4 years 9 months. HIV was initially treated with zidovudine. For the last >10 years he has received didanosine, lamivudine, and nelfinavir. CML was treated with Interferon alfa (INF-alpha) for >10 years and a brief course of hydroxyurea (HU). He remained in chronic phase CML since diagnosis however recent molecular monitoring revealed increased BCR/ABL transcripts necessitating a change in therapy to imatinib. The very prolonged chronic phase of CML in this patient has been unexpected especially in light of the underlying congenital HIV infection.

Pediatric squamous cell carcinoma arising in an alpha-fetoprotein-producing mature cystic teratoma of the mandible

Teratomas, most often diagnosed in younger patients, represent the most frequently identified subtype of pediatric germ cell tumors. It is very uncommon for teratomas to present in the head and neck region and demonstrate malignant transformation. We present a case of squamous cell carcinoma arising in an alpha-fetoprotein-producing cystic teratoma of the mandible in a 2-year-old female that is, to the best of our knowledge, the first such published report. The patient was treated with surgical excision along with chemotherapy and has remained disease-free 2 years after the conclusion of therapy.

Hearing loss, quality of life, and academic problems in long-term neuroblastoma survivors: a report from the Children's Oncology Group

OBJECTIVES

Among a cohort of long-term neuroblastoma survivors, our aims were to (1) assess the association between treatment intensity and parent-reported hearing loss in the child, (2) evaluate the strength of the association between hearing loss and parent-reported academic and psychosocial difficulties in the child, and (3) examine the association between parent-reported academic and psychosocial difficulties in the child and the child's self-reported quality of life.

PATIENTS AND METHODS

Through a mailed survey that included the Pediatric Quality of Life Inventory 4.0 and an outcomes questionnaire for parents, we evaluated 137 children (aged 8-17 years) who were previously enrolled in 1 of 2 Children's Cancer Group neuroblastoma clinical studies.

RESULTS

Childhood survivors of neuroblastoma who had prevalent hearing loss, as reported by their parents, had at least twice the risk of an identified problem with reading skills, math skills, and/or attention and a similarly higher risk of a general learning disability and/or special educational needs than did neuroblastoma survivors without hearing loss. Consistent with this finding, hearing loss was associated with a 10-point-lower mean score in the school-functioning scale of the Pediatric Quality of Life Inventory 4.0. We also observed a clear pattern of poorer self-reported quality-of-life scores among children with parent-reported academic and psychosocial problems compared with those without such problems, particularly with school functioning, even after controlling for reported hearing loss.

CONCLUSIONS

We found evidence that long-term neuroblastoma survivors, especially those with hearing loss, are at elevated risk for academic learning problems and psychosocial difficulties. We also found strong concordance between parent-reported learning problems in the child and indications of distress in the child's self-reported quality of life.

MLL–SEPT6 fusion transcript with a novel sequence in an infant with acute myeloid leukemia

The MLL gene at 11q23 is a site of frequent rearrangement in acute leukemia with multiple fusion partners. A relatively uncommon rearrangement, associated with infant AML-M4, fuses the MLL and SEPT6 genes. SEPT6, located at Xq24, is a member of a family of mammalian septins involved in diverse functions such as cytokinesis, cell polarity, and oncogenesis. We describe the case of an infant with acute myelogenous leukemia who showed cytogenetic evidence of rearrangement between 11q23 and Xq24 regions. Fluorescence in situ hybridization analysis suggested a possible break in the MLL gene, and molecular analysis using reverse transcriptase-polymerase chain reaction followed by sequencing confirmed the expression of an MLL-SEPT6 fusion transcript with a novel sequence. The findings emphasize the importance of combined cytogenetic and molecular analyses in the workup of acute leukemia, especially in those leukemias that occur infrequently.

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.

Favorable prognosis for patients 12 to 18 months of age with stage 4 nonamplified MYCN neuroblastoma: a Children's Cancer Group Study

PURPOSE

The long-term survival of children between age 12 and 24 months with stage 4 neuroblastoma and nonamplified MYCN (MYCN-NA) has not been defined previously.

PATIENTS AND METHODS

Survival for stage 4 MYCN-NA neuroblastoma patients enrolled onto Children's Cancer Group (CCG) protocols 321P2 (1986 to 1991) and 3891 (1991 to 1996) was analyzed. Treatment consisted of intensive alkylator-based induction chemotherapy with or without autologous bone marrow transplantation (ABMT) with or without 13 cis-retinoic acid. Survival was analyzed by age strata less than 12, 12 to 18, 18 to 24, and more than 24 months at diagnosis. Patients younger than 12 months were treated on the moderate-intensity CCG protocol 3881.

RESULTS

Forty-three patients with stage 4 MYCN-NA disease enrolled onto CCG-321P2 (n = 17) or CCG-3891 (n = 26) were between 12 and 24 months of age at diagnosis. After a median follow-up of 94 months (range, 4 to 140 months), the 6-year event-free survival (EFS) for the 12- to 18-month age group was superior to that of the 18- to 24-month age group (74% +/- 8% v 31% +/- 12%; P = .008). The EFS for children older than 24 months with stage 4 MYCN-NA neuroblastoma was 23% +/- 3%, and for children younger than 12 months was 92% +/- 3%.

CONCLUSION

Children diagnosed with stage 4 MYCN-NA neuroblastoma in the second year of life form a transitional group between infants and older children in terms of prognosis. Patients between 12 and 18 months of age have significantly better long-term survival than that of older children treated with intensive chemotherapy with or without ABMT. These patients may not benefit from additional intensification of therapy beyond that provided in earlier clinical trials and may even maintain this high survival rate with less intensive therapy.

Spinal cord neurofibrillary pathology in Alzheimer disease and Guam Parkinsonism-dementia complex

We examined spinal cords of neurodegenerative disease patients and controls living on the Island of Guam and in the continental United States. These patients had pathologically confirmed parkinsonism dementia-complex (PDC) with or without amyotrophic lateral sclerosis (ALS), or Alzheimer disease (AD), respectively. Nearly all of the spinal cords examined from both groups of patients contained neurofibrillary tangles (NFT). The immunohistochemical profile of these NFTs indicates that they are composed of hyperphosphorylated tau protein like their counterparts in the brains of these patients. Western blot analysis confirmed this by revealing that sarcosyl insoluble tau in spinal cord extracts from patients with NFTs exhibited the presence of all 6 tau isoforms similar to that from AD and ALS/PDC cortical gray matter.

Alpha-synuclein in familial Alzheimer disease: epitope mapping parallels dementia with Lewy bodies and Parkinson disease

BACKGROUND

Alpha-synuclein is a major component of Lewy bodies (LBs) in Parkinson disease and dementia with LBs and of glial cytoplasmic inclusions in multiple system atrophy. However, epitope mapping for alpha-synuclein is distinctive in different neurodegenerative diseases. The reasons for this are poorly understood but may reflect fundamental differences in disease mechanisms.

OBJECTIVE

To investigate the alpha-synuclein epitope mapping properties of LBs in familial Alzheimer disease.

DESIGN AND SETTING

We compared LBs in familial Alzheimer disease with those in synucleinopathies by probing 6 brains of persons with familial Alzheimer disease using a panel of antibodies to epitopes spanning the alpha-synuclein protein. Results were compared with data from brains of persons with Parkinson disease, dementia with LBs, and multiple system atrophy.

RESULTS

The brains of persons with familial Alzheimer disease showed consistent staining of LBs with all antibodies, similar to Parkinson disease and dementia with LBs but different from alpha-synuclein aggregates that occurred in multiple system atrophy.

CONCLUSIONS

These data suggest that the epitope profiles of alpha-synuclein in LBs are similar, regardless of whether the biological trigger is related to synuclein or a different genetic pathway. These findings support the hypothesis that the mechanism of alpha-synuclein aggregation is the same within cell types but distinctive between cell types.

Tau isoform profile and phosphorylation state in dementia pugilistica recapitulate Alzheimer's disease

Insights into mechanisms of familial Alzheimer's disease (AD) caused by genetic mutations have emerged rapidly compared to sporadic AD. Indeed, despite identification of several sporadic AD risk factors, it remains enigmatic how or why they predispose to neurodegenerative disease. For example, traumatic brain injury (TBI) predisposes to AD, and recurrent TBI in career boxers may cause a progressive memory disorder associated with AD-like brain pathology known as dementia pugilistica (DP). Although the reasons for this are unknown, repeated TBI may cause DP by mechanisms similar to those involved in AD. To investigate this possibility, we compared the molecular profile of tau pathologies in DP with those in AD and showed that the same tau epitopes map to filamentous tau inclusions in AD and DP brains, while the abnormal tau proteins isolated from DP brains are indistinguishable from the six abnormally phosphorylated brain tau isoforms in AD brains. Thus, these data suggest that recurrent TBI may cause DP by activating pathological mechanisms similar to those that cause brain degeneration due to accumulations of filamentous tau lesions in AD, and similar, albeit attenuated, activation of these processes by a single TBI may increase susceptibility to sporadic AD decades after the event.

Differential expression in an antisense MYCN neuroblastoma model

BACKGROUND

A previously published antisense MYCN-expressing model system was utilized to identify genes whose expression is altered by the down-regulation of MYCN by AS MYCN.

RESULTS

Differential display comparing nontransfected human NB NBL-S cells to three AS MYCN-expressing cell lines (NBAS-4, -5, and -6) yielded nine differentially expressed cDNAs designated NDDE:1-9, for MYCN-dependent differential expression genes. A GenBank search revealed matches for seven of the nine cDNAs. Differential expression was confirmed for five of the cDNAs by Northern blot analysis.

RESULTS

NDDE:8 is up-regulated in the AS MYCN-expressing clones and shares homology with the EB1 clone p53-induced gene (PRG3). NDDE:2 is up-regulated in the high-expressing N-myc protein NBL-S cells and shares homology with a 27 kD heat shock protein PAN1 clone. Further analysis of all five cDNAs might further elucidate the targets of MYCN in NB.

Tau epitopes in spinal cord neurofibrillary lesions in Chamorros of Guam

We examined spinal cord sections from Guamanian Chamorros with or without amyotrophic lateral sclerosis or parkinsonism-dementia complex using immunohistochemistry and antibodies to epitopes that span the length of tau to characterize the tau epitope profile of neurofibrillary tangles in these spinal cords. Most (16/20) spinal cords, including some from Chamorros without documented clinical disease, contained tangles with a tau epitope profile similar to the tangles found in the forebrain and brain stem of these patients.

Synergy between 5' and 3' flanking regions of the human tyrosine hydroxylase gene ensures specific, high-level expression in neuroblastoma cells

Factors regulating tyrosine hydroxylase (TH) gene transcription are of major importance in the studies of malignant and degenerative diseases of catecholamine-synthesizing tissues. In this study, we used transient transfection of a reporter gene to show that high-level, tissue-specific TH expression was only achieved when the reporter gene was cloned between a 5' TH promoter sequence (-513-+1), and, a 3' TH gene flanking sequence (end of exon 14-+976). We also show that TH mRNA expression level is closely linked to the expression level of the proto-oncogene, MYCN in neuroblastoma tumor cell lines. Taken together our data indicate that MYCN may regulate TH expression in neuroblastoma cells, but not through binding to the 5' or 3' TH gene flanking sequences used in our experiments.

Long-term deep brain stimulation in a patient with essential tremor: clinical response and postmortem correlation with stimulator termination sites in ventral thalamus. Case report

Essential tremor can be suppressed with chronic, bilateral deep brain stimulation (DBS) of the ventralis intermedius nucleus (Vim), the cerebellar receiving area of the motor thalamus. The goal in this study was to correlate the location of the electrodes with the clinical efficacy of DBS in a patient with essential tremor. The authors report on a woman with essential tremor in whom chronic bilateral DBS directed to the ventral thalamus produced adequate tremor suppression until her death from unrelated causes 16 months after placement of the electrodes. Neuropathological postmortem studies of the brain in this patient demonstrated that both stimulators terminated in the Vim region of the thalamus, and that chronic DBS elicited minor reactive changes confined to the immediate vicinity of the electrode tracks. Although the authors could not identify neuropathological abnormalities specific to essential tremor, they believe that suppression of essential tremor by chronic DBS correlates with bilateral termination of the stimulators in the Vim region of the thalamus.

Alpha-synuclein cortical Lewy bodies correlate with dementia in Parkinson's disease

BACKGROUND

Dementia is a frequent complication of idiopathic parkinsonism or PD, usually occurring later in the protracted course of the illness. The primary site of neuropathologic change in PD is the substantia nigra, but the neuropathologic and molecular basis of dementia in PD is less clear. Although Alzheimer's pathology has been a frequent finding, recent advances in immunostaining of alpha-synuclein have suggested the possible importance of cortical Lewy bodies (CLBs) in the brains of demented patients with PD.

METHODS

The brains of 22 demented and 20 nondemented patients with a clinical and neuropathologic diagnosis of PD were evaluated with standard neuropathologic techniques. In addition, CLBs and dystrophic neurites were identified immunohistochemically with antibodies specific for alpha-synuclein and ubiquitin; plaques and tangles were identified by staining with thioflavine S. Associations between dementia status and pathologic markers were tested with logistic regression.

RESULTS

CLBs positive for alpha-synuclein are highly sensitive (91%) and specific (90%) neuropathologic markers of dementia in PD and slightly more sensitive than ubiquitin-positive CLBs. They are better indicators of dementia than neurofibrillary tangles, amyloid plaques, or dystrophic neurites.

CONCLUSION

CLBs detected by alpha-synuclein antibodies in patients with PD are a more sensitive and specific correlate of dementia than the presence of Alzheimer's pathology, which was present in a minority of the cases in this series.

Biologic factors determine prognosis in infants with stage IV neuroblastoma: A prospective Children's Cancer Group study

PURPOSE

A prospective Children's Cancer Group study, CCG-3881, has been completed to determine if a more accurate prediction of prognosis by biologic features can identify subgroups of infants with stage IV neuroblastoma (NBL) who require differing intensities of treatment.

PATIENTS AND METHODS

One hundred thirty-four infants were registered from June 1989 to August 1995, with a median follow-up of 47.1 months (range, 0 to 88 months). The biologic factors examined were tumor MYCN copy number, Shimada histopathologic classification, serum ferritin, and bone marrow immunocytology (sensitivity, one tumor cell per 10(5) bone marrow cells). Patients treated on CCG-3881 (n = 116) received four-drug chemotherapy for 9 months (cisplatin, cyclophosphamide, doxorubicin, and etoposide), with surgery and local radiation to residual disease. After January 1991, all subsequent infants with tumor MYCN amplification (n = 18) were transferred after one cycle of therapy to the high-risk CCG-3891 protocol (open January 1991 to April 1996) for more intensive treatment.

RESULTS

The 3-year event-free survival (EFS) and overall survival (mean +/- SD) for the 134 infants were 63% +/- 5% and 71% +/- 5%, respectively. Patients whose tumors were without MYCN amplification had a 93% +/- 4% 3-year EFS, whereas those with amplified MYCN had a 10% +/- 7% 3-year EFS (P <. 0001). Each of the other biologic features studied had prognostic significance in univariate analysis but not after stratifying by MYCN copy number.

CONCLUSION

Infants less than 1 year of age at diagnosis with stage IV NBL have a much improved outcome compared with children >/= 1 year of age. Nonamplified MYCN tumors identify a group of infants with a 93% +/- 4% EFS, whereas amplified MYCN copy number clearly identifies patients who are unlikely to survive despite intensive chemotherapy.

AMY plaques in familial AD: comparison with sporadic Alzheimer's disease

OBJECTIVE

To assess AMY expression in familial AD (FAD).

BACKGROUND

The discovery of nonbeta-amyloid (Abeta), plaque-like deposits composed of a 100-kd protein (AMY) in sporadic AD (SAD) brains prompted us to determine whether these plaques (AMY plaques) also occur in AD due to mutations of the presenilin-1 (PS-1), presenilin-2 (PS-2), or the amyloid precursor protein (APP) genes.

METHODS

We used immunohistochemistry and confocal laser scanning microscopy to probe the brains of 22 patients with FAD (13 with PS-1, 5 with PS-2, and 4 with APP mutations) and 14 patients with SAD.

RESULTS

AMY plaques were present in all SAD and FAD brains, including an FAD/PS-1 brain from an individual with preclinical disease. The morphology of AMY plaques in SAD and FAD brains was indistinguishable, but they differed from Abeta deposits because AMY plaques lacked an immunoreactive core. AMY plaques sometimes colocalized with Abeta(x-42) deposits, but they did not colocalize with Abeta(x-40) plaque cores in either SAD or FAD brains. The percent of cortical area occupied by AMY was greater in FAD than in SAD brains (mean percent area = 9.8% and 5.9%, t = 2.487, p = 0.018). In particular, APP and PS-1 cases had more AMY deposition than PS-2 or SAD cases (12.9%, 10.5%, 6.2% in APP, PS-1, and PS-2 AD).

CONCLUSIONS

AMY plaques are consistently present in familial AD due to presenilin-1 (PS-1), PS-2, and amyloid precursor protein mutations, and they can begin to accumulate before the emergence of dementia.

Spatial relationship of AMY protein deposits and different species of Abeta peptides in amyloid plaques of the Alzheimer disease brain

To further define the spatial relationship of "AMY" plaques detected by antibodies to an unidentified 100 kD AMY protein and amyloid plaques in Alzheimer disease (AD) brains, double immunofluorescence studies were performed with an anti-AMY antibody and a panel of antibodies to different species of Abeta peptides. We report substantial colocalization of AMY immunoreactive plaques with amyloid plaques labeled by antibodies to species of Abeta starting at position 3 with a pyroglutamate modified glutamic acid, however AMY immunoreactive deposits colocalized to a lesser degree with amyloid plaques labeled by antibodies to other variants of the Abeta peptide. Moreover, different immunohistochemical parameters influenced the extent to which colocalization of AMY deposits and Abeta immunoreactive plaques was demonstrable. We conclude that deposits of distinct species of Abeta peptides differentially colocalize with one another and with AMY plaques in the AD brain.

Traumatic brain injury in young, amyloid-beta peptide overexpressing transgenic mice induces marked ipsilateral hippocampal atrophy and diminished Abeta deposition during aging

Traumatic brain injury (TBI) is an epigenetic risk factor for Alzheimer's disease (AD). To test the hypothesis that TBI contributes to the onset and/or progression of AD-like beta-amyloid peptide (Abeta) deposits, we studied the long-term effects of TBI in transgenic mice that overexpress human Abeta from a mutant Abeta precursor protein (APP) minigene driven by a platelet derived (PD) growth factor promoter (PDAPP mice). TBI was induced in 4-month-old PDAPP and wild type (WT) mice by controlled cortical impact (CCI). Because Abeta begins to deposit progressively in the PDAPP brain by 6 months, we examined WT and PDAPP mice at 2, 5, and 8 months after TBI or sham treatment (i.e., at 6, 9, and 12 months of age). Hippocampal atrophy in the PDAPP mice was more severe ipsilateral versus contralateral to TBI, and immunohistochemical studies with antibodies to different Abeta peptides demonstrated a statistically significant reduction in hippocampus and cingulate cortex Abeta deposits ipsilateral versus contralateral to CCI in 9-12 month-old PDAPP mice. Hippocampal atrophy and reduced Abeta deposits were not seen in hippocampus or cingulate cortex of sham-injured PDAPP mice or in any WT mice. These data suggest that the vulnerability of brain cells to Abeta toxicity increases and that the accumulation of Abeta deposits decrease in the penumbra of CCI months after TBI. Thus, in addition to providing unique opportunities for elucidating genetic mechanisms of AD, transgenic mice that recapitulate AD pathology also may be relevant animal models for investigating the poorly understood role that TBI and other epigenetic risk factors play in the onset and/or progression of AD.

Altered expression of the MYCN oncogene modulates MRP gene expression and response to cytotoxic drugs in neuroblastoma cells

We have recently shown a close correlation between expression of the Multidrug Resistance-associated Protein (MRP) gene and the MYCN oncogene and provided evidence that high MRP expression is a powerful independent predictor of poor outcome in neuroblastoma (Norris et al., New Engl. J. Med., 334, 231-238, 1996). The effect of MYCN down-regulation on MRP expression and response to cytotoxic drugs was investigated in NBL-S neuroblastoma cells transfected with MYCN antisense RNA constructs. Concomitant with MYCN down-regulation, the level of MRP expression was decreased in the NBAS-4 and NBAS-5 antisense transfectants. These cells demonstrated significantly increased sensitivity to the high affinity MRP substrates vincristine, doxorubicin, sodium arsenate and potassium antimony tartrate, but not to the poor MRP substrates, taxol or cisplatin. Similarly, transfection of full-length MYCN cDNA into SH-EP neuroblastoma cells resulted in increased MRP expression and significantly increased resistance specifically to MRP substrates. The results provide evidence for the MYCN oncogene influencing cytotoxic drug response via regulation of MRP gene expression. Our data also provide a link between the malignant and chemoresistant phenotypes of this childhood malignancy.

Tau pathology in a family with dementia and a P301L mutation in tau

Familial forms of frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) have recently been associated with coding region and intronic mutations in the tau gene. Here we report our findings on 2 affected siblings from a family with early-onset dementia, characterized by extensive tau pathology and a Pro to Leu mutation at codon 301 of tau. The proband, a 55-year-old woman, and her 63-year-old brother died after a progressive dementing illness clinically diagnosed as Alzheimer disease. Their mother, 2 sisters, maternal aunt and uncle, and several cousins were also affected. Autopsy in both cases revealed frontotemporal atrophy and degeneration of basal ganglia and substantia nigra. Sequencing of exon 10 of the tau gene revealed a C to T transition at codon 301, resulting in a Pro to Leu substitution. Widespread neuronal and glial inclusions, neuropil threads, and astrocytic plaques similar to those seen in corticobasal degeneration were labeled with a battery of antibodies to phosphorylation-dependent and phosphorylation-independent epitopes spanning the entire tau sequence. Isolated tau filaments had the morphology of narrow twisted ribbons. Sarkosyl-insoluble tau exhibited 2 major bands of 64 and 68 kDa and a minor 72 kDa band, similar to the pattern seen in a familial tauopathy associated with an intronic tau mutation. These pathological tau bands predominantly contained the subset of tau isoforms with 4 microtubule-binding repeats selectively affected by the P301L missense mutation. Our findings emphasize the phenotypic and genetic heterogeneity of tauopathies and highlight intriguing links between FTDP-17 and other neurodegenerative diseases.