SNP array profiling of childhood adrenocortical tumors reveals distinct pathways of tumorigenesis and highlights candidate driver genes

Childhood adrenocortical tumors (ACT) are rare malignancies, except in southern Brazil, where a higher incidence rate is associated to a high frequency of the founder R337H TP53 mutation. To date, copy number alterations in these tumors have only been analyzed by low-resolution comparative genomic hybridization.

Disabling c-Myc in childhood medulloblastoma and atypical teratoid/rhabdoid tumor cells by the potent G-quadruplex interactive agent S2T1-6OTD

We investigated here the effects of S2T1-6OTD, a novel telomestatin derivative that is synthesized to target G-quadruplex-forming DNA sequences, on a representative panel of human medulloblastoma (MB) and atypical teratoid/rhabdoid (AT/RT) childhood brain cancer cell lines. S2T1-6OTD proved to be a potent c-Myc inhibitor through its high-affinity physical interaction with the G-quadruplex structure in the c-Myc promoter. Treatment with S2T1-6OTD reduced the mRNA and protein expressions of c-Myc and hTERT, which is transcriptionally regulated by c-Myc, and decreased the activities of both genes. In remarkable contrast to control cells, short-term (72-hour) treatment with S2T1-6OTD resulted in a dose- and time-dependent antiproliferative effect in all MB and AT/RT brain tumor cell lines tested (IC(50), 0.25-0.39 micromol/L). Under conditions where inhibition of both proliferation and c-Myc activity was observed, S2T1-6OTD treatment decreased the protein expression of the cell cycle activator cyclin-dependent kinase 2 and induced cell cycle arrest. Long-term treatment (5 weeks) with nontoxic concentrations of S2T1-6OTD resulted in a time-dependent (mainly c-Myc-dependent) telomere shortening. This was accompanied by cell growth arrest starting on day 28 followed by cell senescence and induction of apoptosis on day 35 in all of the five cell lines investigated. On in vivo animal testing, S2T1-6OTD may well represent a novel therapeutic strategy for childhood brain tumors.

Atypical presentation of a hormonally active adrenocortical tumor in an adolescent leading to delayed diagnosis

Adrenocortical tumors are rare in children and present with variable signs depending on the type of hormone excess. We herein describe the unusual presentation of a child with adrenocortical tumor and introduce the concept of in vitro chemosensitivity testing. CASE REPORT: A 10.5-year-old girl presented with hypertrichosis/hirsutism and weight loss. The weight loss and behavioral problems, associated with halted puberty and growth, led to the initial diagnosis of anorexia nervosa. However, subsequent weight gain but persisting arrest in growth and puberty and the appearance of central fat distribution prompted further evaluation. RESULTS AND FOLLOW-UP: 24h-urine free cortisol was elevated. Morning plasma ACTH was undetectable, while cortisol was elevated and circadian rhythmicity was absent. Thus a hormonally active adrenal cortical tumor (ACT) was suspected. On magnetic resonance imaging (MRI) a unilateral, encapsulated tumor was found which was subsequently removed surgically. Tissue was investigated histologically and for chemosensitivity in primary cell cultures. Although there were some risk factors for malignancy, the tumor was found to be a typical adenoma. Despite this histology, tumor cells survived in culture and were sensitive to cisplatin in combination with gemcitabine or paclitaxel. At surgery, the patient was started on hydrocortisone replacement which was unsuccessfully tapered over 3 months. Full recovery of the hypothalamus-pituitary-adrenal axis occurred only after 3 years. CONCLUSIONS: The diagnosis of a hormonally active adrenocortical tumor is often delayed because of atypical presentation. Cortisol replacement following unilateral tumor excision is mandatory and may be required for months or years. Individualized chemosensitivity studies carried out on primary cultures established from the tumor tissue itself may provide a tool in evaluating the effectiveness of chemotherapeutic drugs in the event that the adrenocortical tumor may prove to be carcinoma.

Brain tumors in children and adolescents and exposure to animals and farm life: a multicenter case-control study (CEFALO)

The etiology of brain tumors in children and adolescents is largely unknown, and very few environmental risk factors have been identified. The aim of this study was to examine the relationship between pre- or postnatal animal contacts or farm exposures and the risk of childhood brain tumors (CBTs), since infectious agents may pose a risk factor and a proposed mechanism is transferral of infectious agents from animals to humans.

The quassinoid derivative NBT-272 targets both the AKT and ERK signaling pathways in embryonal tumors

The quassinoid analogue NBT-272 has been reported to inhibit MYC, thus warranting a further effort 7to better understand its preclinical properties in models of embryonal tumors (ET), a family of childhood malignancies sharing relevant biological and genetic features such as deregulated expression of MYC oncogenes. In our study, NBT-272 displayed a strong antiproliferative activity in vitro that resulted from the combination of diverse biological effects, ranging from G(1)/S arrest of the cell cycle to apoptosis and autophagy. The compound prevented the full activation of both eukaryotic translation initiation factor 4E (eIF4E) and its binding protein 4EBP-1, regulating cap-dependent protein translation. Interestingly, all responses induced by NBT-272 in ET could be attributed to interference with 2 main proproliferative signaling pathways, that is, the AKT and the MEK/extracellular signal-regulated kinase pathways. These findings also suggested that the depleting effect of NBT-272 on MYC protein expression occurred via indirect mechanisms, rather than selective inhibition. Finally, the ability of NBT-272 to arrest tumor growth in a xenograft model of neuroblastoma plays a role in the strong antitumor activity of this compound, both in vitro and in vivo, with its potential to target cell-survival pathways that are relevant for the development and progression of ET.

Health care use of long-term survivors of childhood cancer: the British Childhood Cancer Survivor Study

Purpose Survivors of childhood cancer are at high risk of chronic conditions, but few studies investigated whether this translates into increased health care utilization. We compared health care service utilization between childhood cancer survivors and the general British population and investigated potential risk factors. Methods We used data from the British Childhood Cancer Survivor Study, a population-based cohort of 17,981 individuals diagnosed with childhood cancer (1940-1991) and surviving ≥ 5 years. Frequency of talks to a doctor, hospital outpatient visits, and day-patient and inpatient hospitalizations were ascertained by questionnaire in 10,483 survivors and were compared with the General Household Survey 2002 data by using logistic regression. Results Among survivors, 16.5% had talked to a doctor in the last 2 weeks, 25.5% had attended the outpatient department of a hospital in the last 3 months, 11.9% had been hospitalized as a day patient in the last 12 months, and 9.8% had been hospitalized as an inpatient in the last 12 months. Survivors had talked slightly more often to a doctor than the general population (odds ratio [OR], 1.2; 95% CI, 1.1 to 1.3) and experienced increased hospital outpatient visits (OR, 2.5; 95% CI, 2.3 to 2.8), day-patient hospitalizations (OR, 1.4; 95% CI, 1.3 to 1.6) and inpatient hospitalizations (OR, 1.9; 95% CI, 1.7 to 2.2). Survivors of Hodgkin's lymphoma, neuroblastoma, and Wilms tumor had the highest ORs for day-patient care, whereas survivors of CNS tumors and bone sarcomas had the highest OR for outpatient and inpatient care. The OR of health care use did not vary significantly with age of survivor. Conclusion We have quantified how excess morbidity experienced by survivors of childhood cancer translates into increased use of health care facilities.

Physical performance limitations in adolescent and adult survivors of childhood cancer and their siblings

Purpose This study investigates physical performance limitations for sports and daily activities in recently diagnosed childhood cancer survivors and siblings. Methods The Swiss Childhood Cancer Survivor Study sent a questionnaire to all survivors (≥16 years) registered in the Swiss Childhood Cancer Registry, who survived >5 years and were diagnosed 1976–2003 aged <16 years. Siblings received similar questionnaires. We assessed two types of physical performance limitations: 1) limitations in sports; 2) limitations in daily activities (using SF-36 physical function score). We compared results between survivors diagnosed before and after 1990 and determined predictors for both types of limitations by multivariable logistic regression. Results The sample included 1038 survivors and 534 siblings. Overall, 96 survivors (9.5%) and 7 siblings (1.1%) reported a limitation in sports (Odds ratio 5.5, 95%CI 2.9-10.4, p<0.001), mainly caused by musculoskeletal and neurological problems. Findings were even more pronounced for children diagnosed more recently (OR 4.8, CI 2.4–9.6 and 8.3, CI 3.7–18.8 for those diagnosed <1990 and ≥1990, respectively; p = 0.025). Mean physical function score for limitations in daily activities was 49.6 (CI 48.9–50.4) in survivors and 53.1 (CI 52.5–53.7) in siblings (p<0.001). Again, differences tended to be larger in children diagnosed more recently. Survivors of bone tumors, CNS tumors and retinoblastoma and children treated with radiotherapy were most strongly affected. Conclusion Survivors of childhood cancer, even those diagnosed recently and treated with modern protocols, remain at high risk for physical performance limitations. Treatment and follow-up care should include tailored interventions to mitigate these late effects in high-risk patients.

RNA interference-mediated c-MYC inhibition prevents cell growth and decreases sensitivity to radio- and chemotherapy in childhood medulloblastoma cells

BACKGROUND: With current treatment strategies, nearly half of all medulloblastoma (MB) patients die from progressive tumors. Accordingly, the identification of novel therapeutic strategies remains a major goal. Deregulation of c-MYC is evident in numerous human cancers. In MB, over-expression of c-MYC has been shown to cause anaplasia and correlate with unfavorable prognosis. METHODS: To study the role of c-MYC in MB biology, we down-regulated c-MYC expression by using small interfering RNA (siRNA) and investigated changes in cellular proliferation, cell cycle analysis, apoptosis, telomere maintenance, and response to ionizing radiation (IR) and chemotherapeutics in a representative panel of human MB cell lines expressing different levels of c-MYC (DAOY wild-type, DAOY transfected with the empty vector, DAOY transfected with c-MYC, D341, and D425). RESULTS: siRNA-mediated c-MYC down-regulation resulted in an inhibition of cellular proliferation and clonogenic growth, inhibition of G1-S phase cell cycle progression, and a decrease in human telomerase reverse transcriptase (hTERT) expression and telomerase activity. On the other hand, down-regulation of c-MYC reduced apoptosis and decreased the sensitivity of human MB cells to IR, cisplatin, and etoposide. This effect was more pronounced in DAOY cells expressing high levels of c-MYC when compared with DAOY wild-type or DAOY cells transfected with the empty vector. CONCLUSION: In human MB cells, in addition to its roles in growth and proliferation, c-MYC is also a potent inducer of apoptosis. Therefore, targeting c-MYC might be of therapeutic benefit when used sequentially with chemo- and radiotherapy rather than concomitantly.

Domestic radon exposure and risk of childhood cancer: a prospective census-based cohort study

Background: In contrast with established evidence linking high doses of ionizing radiation with childhood cancer, research on low-dose ionizing radiation and childhood cancer has produced inconsistent results. Objective: We investigated the association between domestic radon exposure and childhood cancers, particularly leukemia and central nervous system (CNS) tumors. Methods: We conducted a nationwide census-based cohort study including all children < 16 years of age living in Switzerland on 5 December 2000, the date of the 2000 census. Follow-up lasted until the date of diagnosis, death, emigration, a child’s 16th birthday, or 31 December 2008. Domestic radon levels were estimated for each individual home address using a model developed and validated based on approximately 45,000 measurements taken throughout Switzerland. Data were analyzed with Cox proportional hazard models adjusted for child age, child sex, birth order, parents’ socioeconomic status, environmental gamma radiation, and period effects. Results: In total, 997 childhood cancer cases were included in the study. Compared with children exposed to a radon concentration below the median (< 77.7 Bq/m3), adjusted hazard ratios for children with exposure ≥ the 90th percentile (≥ 139.9 Bq/m3) were 0.93 (95% CI: 0.74, 1.16) for all cancers, 0.95 (95% CI: 0.63, 1.43) for all leukemias, 0.90 (95% CI: 0.56, 1.43) for acute lymphoblastic leukemia, and 1.05 (95% CI: 0.68, 1.61) for CNS tumors. Conclusions: We did not find evidence that domestic radon exposure is associated with childhood cancer, despite relatively high radon levels in Switzerland.

Exposure to Radio-Frequency Electromagnetic Fields From Broadcast Transmitters and Risk of Childhood Cancer: A Census-based Cohort Study

We investigated the association between exposure to radio-frequency electromagnetic fields (RF-EMFs) from broadcast transmitters and childhood cancer. First, we conducted a time-to-event analysis including children under age 16 years living in Switzerland on December 5, 2000. Follow-up lasted until December 31, 2008. Second, all children living in Switzerland for some time between 1985 and 2008 were included in an incidence density cohort. RF-EMF exposure from broadcast transmitters was modeled. Based on 997 cancer cases, adjusted hazard ratios in the time-to-event analysis for the highest exposure category (>0.2 V/m) as compared with the reference category (<0.05 V/m) were 1.03 (95% confidence interval (CI): 0.74, 1.43) for all cancers, 0.55 (95% CI: 0.26, 1.19) for childhood leukemia, and 1.68 (95% CI: 0.98, 2.91) for childhood central nervous system (CNS) tumors. Results of the incidence density analysis, based on 4,246 cancer cases, were similar for all types of cancer and leukemia but did not indicate a CNS tumor risk (incidence rate ratio = 1.03, 95% CI: 0.73, 1.46). This large census-based cohort study did not suggest an association between predicted RF-EMF exposure from broadcasting and childhood leukemia. Results for CNS tumors were less consistent, but the most comprehensive analysis did not suggest an association.

NOTCH ligands JAG1 and JAG2 as critical pro-survival factors in childhood medulloblastoma.

Medulloblastoma (MB), the most common pediatric malignant brain cancer, typically arises as pathological result of deregulated developmental pathways, including the NOTCH signaling cascade. Unlike the evidence supporting a role for NOTCH receptors in MB development, the pathological functions of NOTCH ligands remain largely unexplored. By examining the expression in large cohorts of MB primary tumors, and in established in vitro MB models, this research study demonstrates that MB cells bear abnormal levels of distinct NOTCH ligands. We explored the potential association between NOTCH ligands and the clinical outcome of MB patients, and investigated the rational of inhibiting NOTCH signaling by targeting specific ligands to ultimately provide therapeutic benefits in MB. The research revealed a significant over-expression of ligand JAG1 in the vast majority of MBs, and proved that JAG1 mediates pro-proliferative signals via activation of NOTCH2 receptor and induction of HES1 expression, thus representing an attractive therapeutic target. Furthermore, we could identify a clinically relevant association between ligand JAG2 and the oncogene MYC, specific for MYC-driven Group 3 MB cases. We describe for the first time a mechanistic link between the oncogene MYC and NOTCH pathway in MB, by identifying JAG2 as MYC target, and by showing that MB cells acquire induced expression of JAG2 through MYC-induced transcriptional activation. Finally, the positive correlation of MYC and JAG2 also with aggressive anaplastic tumors and highly metastatic MB stages suggested that high JAG2 expression may be useful as additional marker to identify aggressive MBs.

Concentration, Working Speed and Memory: Cognitive Problems in Young Childhood Cancer Survivors and Their Siblings.

BACKGROUND Cognitive problems can have a negative effect on a person's education, but little is known about cognitive problems in young childhood cancer survivors (survivors). This study compared cognitive problems between survivors and their siblings, determined if cognitive problems decreased during recent treatment periods and identified characteristics associated with the presence of a cognitive problem in survivors. METHODS As part of the Swiss Childhood Cancer Survivor Study, a questionnaire was sent to all survivors, aged 8-20 years, registered in the Swiss Childhood Cancer Registry, diagnosed at age <16 years, who had survived ≥5 years. Parent-reported (aged 8-15 years) and self-reported (aged 16-20 years) cognitive problems (concentration, working speed, memory) were compared between survivors and siblings. Multivariable logistic regression was used to identify characteristics associated with cognitive problems in survivors. RESULTS Data from 840 survivors and 247 siblings were analyzed. More often than their siblings, survivors reported problems with concentration (12% vs. 6%; P = 0.020), slow working speed (20% vs. 8%; P = 0.001) or memory (33% vs. 15%; P < 0.001). Survivors from all treatment periods were more likely to report a cognitive problem than were siblings. Survivors of CNS tumors (OR = 2.82 compared to leukemia survivors, P < 0.001) and those who had received cranial irradiation (OR = 2.10, P = 0.010) were most severely affected. CONCLUSION Childhood cancer survivors, even those treated recently (2001-2005), remain at risk to develop cognitive problems, suggesting a need to improve therapies. Survivors with cognitive problems should be given the opportunity to enter special education programs. Pediatr Blood Cancer © 2014 Wiley Periodicals, Inc.

Background Ionizing Radiation and the Risk of Childhood Cancer: A Census-Based Nationwide Cohort Study

BACKGROUND Exposure to medium or high doses of ionizing radiation is a known risk factor for cancer in children. The extent to which low dose radiation from natural sources contributes to the risk of childhood cancer remains unclear. OBJECTIVES In a nationwide census-based cohort study, we investigated whether the incidence of childhood cancer was associated with background radiation from terrestrial gamma and cosmic rays. METHODS Children aged <16 years in the Swiss National Censuses in 1990 and 2000 were included. The follow-up period lasted until 2008 and incident cancer cases were identified from the Swiss Childhood Cancer Registry. A radiation model was used to predict dose rates from terrestrial and cosmic radiation at locations of residence. Cox regression models were used to assess associations between cancer risk and dose rates and cumulative dose since birth. RESULTS Among 2,093,660 children included at census, 1,782 incident cases of cancer were identified including 530 with leukemia, 328 with lymphoma, and 423 with a tumor of the central nervous system (CNS). Hazard ratios for each mSv increase in cumulative dose of external radiation were 1.03 (95% CI: 1.01, 1.05) for any cancer, 1.04 (1.00, 1.08) for leukemia, 1.01 (0.96, 1.05) for lymphoma, and 1.04 (1.00, 1.08) for CNS tumors. Adjustment for a range of potential confounders had little effect on the results. CONCLUSIONS Our study suggests that background radiation may contribute to the risk of cancer in children including leukemia and CNS tumors.

Health-related quality of life in young survivors of childhood cancer

PURPOSE Childhood cancer and its treatment may affect health-related quality of life (HRQoL) in childhood cancer survivors, but population-based studies in young survivors are scarce. We aimed to: (1) compare HRQoL between young survivors and population norms and (2) find factors that influence parent-reported HRQoL in survivors. METHODS As part of the Swiss Childhood Cancer Survivor Study, a questionnaire was mailed to parents of survivors aged 8-16 years, registered in the Swiss Childhood Cancer Registry, ≥5 years after diagnosis. We used the KIDSCREEN-27 instrument to compare self- and parent-reported HRQoL between survivors (N = 425) and standardized norms in the five dimensions of physical well-being, psychological well-being, autonomy, peers and school environment (mean = 50, SD = 10). We then used multivariable linear regressions to test the influence of socio-demographic and cancer-related factors on HRQoL. RESULTS Self-reported physical well-being was comparable to norms. Other HRQoL dimensions were higher than norms, with the highest mean = 52.2 (p < 0.001) for school environment. Parent-reported HRQoL in survivors was comparable to population norms; only physical well-being was lower (mean = 47.1, p < 0.001), and school environment was higher (mean = 51.1, p = 0.035). Parent-reported HRQoL was lower for survivors of CNS tumors (physical well-being: β = -5.27, p = 0.007; psychological well-being: β = -4.39, p = 0.044; peers β = -5.17, p = 0.028), survivors of neuroblastoma (psychological well-being β = -5.20, p = 0.047), and survivors who had had a relapse (physical well-being β = -5.41, p = 0.005). CONCLUSIONS Assessing HRQoL during follow-up care, with a focus on physical well-being, specific diagnoses (e.g., CNS tumor) and late complications (e.g., relapse) might help to early identify problems and offer support to survivors with reduced HRQoL.

Socioeconomic disparities in childhood cancer survival in Switzerland.

In this study, we investigated whether childhood cancer survival in Switzerland is influenced by socioeconomic status (SES), and if disparities vary by type of cancer and definition of SES (parental education, living condition, area-based SES). Using Cox proportional hazards models, we analyzed 5-year cumulative mortality in all patients registered in the Swiss Childhood Cancer Registry diagnosed 1991-2006 below 16 years. Information on SES was extracted from the Swiss census by probabilistic record linkage. The study included 1602 children (33% with leukemia, 20% with lymphoma, 22% with central nervous system (CNS) tumors); with an overall 5-year survival of 77% (95%CI 75-79%). Higher SES, particularly parents' education, was associated with a lower 5-year cumulative mortality. Results varied by type of cancer with no association for leukemia and particularly strong effects for CNS tumor patients, where mortality hazard ratios for the different SES indicators, comparing the highest with the lowest group, ranged from 0.48 (95%CI: 0.28-0.81) to 0.71 (95%CI: 0.44-1.15). We conclude that even in Switzerland with a high quality health care system and mandatory health insurance, socioeconomic differences in childhood cancer survival persist. Factors causing these survival differences have to be further explored, to facilitate universal access to optimal treatment and finally eliminate social inequalities in childhood cancer survival. This article is protected by copyright. All rights reserved.