Childhood central nervous system (CNS) tumors represent serious diseases. Due to their relative intractability, CNS tumors have surpassed leukemias as the leading cause of death due to cancer in children in the US. 1 From 2014 to 2018, the incidence rate for childhood CNS tumors was approximately 55 cases per million children per year, and the most common tumor types were as-trocytoma and medulloblastoma. 2 In this issue of JAMA, Hargreave et al 3 examined the association between maternal hormonal contraception use and CNS tumors in their offspring. The authors used data from a population-based registry from Denmark and included 1185 063 children born between 1996 and 2014. During 15 335 990 person-years of follow-up (median follow-up, 12.9 years), 725 cases of childhood CNS tumors were diagnosed. Among the mothers, 136 022 had recent hormonal contraception use, 778 843 had previous use, and 270 198 had no use. Combined hormonal contraception showed no association with CNS tumors (incidence rate, 5.0 per 100 000 person-years for children born to mothers with hormonal contraception use ≤3 months before the start of and during pregnancy vs 5.3 per 100 000 person-years for children born to mothers with no use; hazard ratio, 0.95 [95% CI, 0.74-1.23]). No significant associations were observed for different regimens (ie, combined , progestin only) or route of administration (oral, non-oral). The only significant finding was among recent use of progestin-only injections (n = 885 cases), with less than 5 cases of CNS tumors among women with recent use vs no use (haz-ard ratio, 6.74 [95% CI, 2.15-21.15]). However, as the authors acknowledged, there are many reasons to be cautious about the latter finding, including the very small number of exposed children and cases. That other nonoral progestin-only contraceptives were not associated with CNS tumors, with a negative likelihood test indicating that the products in this class may not differ in terms of risk, also suggests no elevation in risk. This may have been a chance finding among the many observations made in the study. Is it biologically plausible that maternal hormonal contraceptives , particularly progestin-only products, could increase the risk of childhood CNS tumors? 4 The authors pointed out that "…hormonal exposure in utero is recognized to cause cancer in exposed offspring," referring to the example of diethylstilbestrol. Maternal diethylstilbestrol ingestion, injection , or vaginal application during fetal organogenesis in the first trimester has been associated with congenital genitouri-nary abnormalities and cervicovaginal clear cell carcinoma in offspring. 5 Diethylstilbestrol readily crosses the placenta and acts through both an estrogen-dependent pathway (ie, through estrogen receptors) and an epigenetic pathway. A second example is 17-α hydroxyprogesterone caproate, a pro-gestin administered during pregnancy to prevent miscarriage in the 1950s and 1960s and preterm birth in the 2000s. In utero exposure has been suggested to increase the risk of cancer in offspring. 6 Based on these examples, it is not entirely implausible that a similar hormone taken during pregnancy might possibly cause cancer in offspring, but additional conditions would have to be met. First, can the hormone cross the pla-centa, and at what stage of pregnancy? The natural analogue of progestins, progesterone, is critical to implantation and has receptors on trophoblast cells. As part of the luteal-placental transition between 4 to 6 weeks after ovulation (ie, 6-8 weeks' gestation), the placenta is able to synthesize pro-gesterone as well as other enzymes to metabolize steroids such as progesterone by the end of the first trimester. Proges-terone can have bidirectional transplacental passage through the mid-to late-gestation placenta in nonhuman primates, with maternal progesterone accounting for only 7% of the steroid in the fetus. 7 Second, if synthetic progestins do cross the placenta, the timing must be considered. Both the diethylstilbestrol and 17-α hydroxyprogesterone caproate examples involved repeated maternal exposure during pregnancy, while the study by Hargreave et al 3 measured recent, shorter exposure, including prior to conception. The half-life of common pro-gestins used in contraception ranges from 12 hours for levonorgestrel (used in intrauterine devices and combined hormonal contraception) to 24 hours for medroxyprogester-one (MPA; used in injectable contraception). A highly effect ive a n d r e ve r s i b l e c o nt r a c e p t ive m e t h o d , d e p o-medroxyprogesterone acetate, is given intramuscularly at a dose of 150 mg every 3 months and acts by ovulation inhibition and endometrium atrophy. After an injection, the observed return to ovulation occurs in 30% to 56% of patients within 6 months and 75% to 100% patients within 12 months. 8 Detailed serial sampling of serum MPA and estra-diol and progesterone levels (to assess drug concentrations and ovulation) shows that MPA levels begin a gradual decline 2 to 3 months after an injection, but can be detectable for 7 to 9 months. However, ovulation occurred only when serum MPA levels were no longer detectable (<20 pg/mL) at 7 to 9 months. 9 In the present study, if maternal ovulation occurred for pregnancy to have happened, mothers were unlikely to have detectable levels of MPA. Therefore, it seems unlikely

Background: Cytomegalovirus (CMV) is among the most common viral infections after solid organ transplantation (SOT). Associations of CMV with cancer risk among SOT recipients have been incompletely evaluated. Methods: The authors used linked data from the US SOT registry and 32 cancer registries. Poisson regression was used to compare cancer incidence across CMV risk groups based on donor (D) and recipient (R) immunoglobulin G (IgG) serostatus: high risk (R-negative/D-positive), moderate risk (R-positive), and low risk (R-negative/D-negative). Results: In total, 247,318 SOT recipients were evaluated during 2000–2017 (R-negative/D-positive, 20.3%; R-positive, 62.9%; R-negative/D-negative, 16.8%). CMV-seropositive recipients were older, more racially/ethnically diverse, and had lower socioeconomic status than CMV-seronegative recipients. Compared with R-negative/D-negative recipients, recipients in the R-negative/D-positive and R-positive groups had a lower incidence of diffuse large B-cell lymphoma (DLBCL; R-negative/D-positive: adjusted incidence rate ratio [aIRR], 0.74; 95% confidence interval [CI], 0.59–0.91; R-positive: aIRR, 0.83; 95% CI, 0.69–1.00). CMV serostatus modified the association between Epstein–Barr virus (EBV) status and DLBCL (p =.0006): DLBCL incidence was increased for EBV R-negative/D-positive recipients (aIRR, 3.46; 95% CI, 1.50–7.95) among CMV R-negative/D-negative recipients but not among the other CMV risk groups. Compared with recipients who were CMV R-negative/D-negative, those who were R-negative/D-positive had a lower incidence of small intestine cancer (aIRR, 0.23; 95% CI, 0.09–0.63), and R-positive recipients had a higher incidence of lung cancer (aIRR, 1.24; 95% CI, 1.05–1.46). CMV status was not associated with risk for other cancers. Conclusions: CMV status was not associated with risk for most cancers among SOT recipients. The inverse association with DLBCL may reflect the protective effects of CMV prophylaxis or treatment with off-target efficacy against EBV infection (the major cause of lymphoma in SOT recipients).

Background: Young children in the household are a known risk factor for maternal CMV infection and consequently, congenital infection in infants. However, little is known about viral shedding in pre-school aged children. Objectives: To estimate the prevalence of CMV DNA shedding and CMV antibodies among healthy children and their mothers. Study Design: A study of children ages 0 through 5 years was undertaken at the 2019 Minnesota State Fair. Children and their mothers were assessed for CMV shedding by procurement of a saliva swab for CMV PCR testing. An optional finger-stick for capillary blood was used to assess CMV antibodies. Results: A total of 109 children and 85 mothers were enrolled. The prevalence of CMV saliva shedding among children (mean age 3.1 years, SE=0.16) and their mothers was 12/109 (11.0%) and 1/85 (1.2%), respectively. The prevalence of CMV DNA among children peaked at 3 years of age (26%) while the mean viral load was greatest at one year of age (236,693 IU/mL). CMV IgG antibodies among those who agreed to a finger-stick were detected in 16/35 mothers (45.7%) and 0/7 children (0%). Mothers of children aged 5 years or greater had the highest seroprevalence (61.5%). Conclusions: The prevalence of CMV salivary shedding in this unselected sample of young children was approximately 11.0%. The overall maternal seroprevalence in our sample was <50%, suggesting these women are at risk for acquisition of a primary CMV infection in subsequent pregnancies.

Although global differences in the incidence of neuroblastoma have been examined, the underlying mechanism has yet to be elucidated. Previous studies have suggested genetic ancestry and human development index (HDI) as contributing factors, but few studies have been conducted at the international level. Here, we aimed to examine whether the frequency of common genomic variation associated with neuroblastoma can affect its risk at the ecological level with consideration of the HDI. Minor allele frequencies (MAFs) for 22 single-nucleotide polymorphisms (SNPs) were abstracted from the Geography of Genetic Variants Browser. The number of incident neuroblastomas for each population was obtained from the Cancer Incidence in Five Continents series. Further, population pseudo-polygenic risk scores (pp-PRSs) were calculated as a sum of MAFs at the population level, each of which was weighted by effect sizes from prior studies. Negative binomial regression was used to estimate the incidence rate ratios (IRRs) and the 95% confidence intervals (CIs) to examine whether differences in MAFs across the population influence the risk of neuroblastoma, with and without adjustment for HDI and whether pp-PRSs can be a predictor of the risk of neuroblastoma. Overall, our results indicated that the neuroblastoma risk associated with variation in SNP frequency could not be differentiated from that of HDI at the ecological level. Additionally, pp-PRSs were not significantly associated with the risk of neuroblastoma (IRR: 0.99, 95% CI: 0.62–1.60). Further study using individual-level data is warranted to minimize the bias related to the use of population-level data in this study.

Background: Pediatric cancer incidence has steadily increased concurrent with rising adult obesity, but

Advances in genome and tissue engineering have spurred significant progress and opportunity for innovation in cancer modeling. Human induced pluripotent stem cells (iPSCs) are an established and powerful tool to study cellular processes in the context of disease-specific genetic backgrounds; however, their application to cancer has been limited by the resistance of many transformed cells to undergo successful reprogramming. Here, we review the status of human iPSC modeling of solid tumors in the context of genetic engineering, including how base and prime editing can be incorporated into "bottom-up"cancer modeling, a term we coined for iPSC-based cancer models using genetic engineering to induce transformation. This approach circumvents the need to reprogram cancer cells while allowing for dissection of the genetic mechanisms underlying transformation, progression, and metastasis with a high degree of precision and control. We also discuss the strengths and limitations of respective engineering approaches and outline experimental considerations for establishing future models.

Background

Background: Though advanced parental age has been definitively linked to

Osteosarcoma (OS) is the most common primary bone tumor in children and adolescents. The etiology of OS is largely unknown but may be informed by comparisons of incidence and trends between geographic regions. Using the Cancer Incidence in Five Continents (CI5) data from 1988 to 2012, we present OS age-standardized incidence rates (ASRs; cases/million) and average annual percent change (AAPC) and 95% confidence interval (CI) by geographic region among the age groups 0-9, 10-19, 20-29, 30-59, 60-79, 0-79. Among the 10-19 age group, we also used the most recent data (2008-2012) to present the ASRs for each country. We observed little variation in OS incidence between geographic regions in 2008-2012 across all age groups. Overall, the ASR for 0-79 ranged from 2 cases per million in Southern Asia to 4.2 in Sub-Saharan Africa. A bimodal distribution in incidence was observed with peaks in the 10-19 and 60-79 age groups across all regions over time. Overall, OS incidence was relatively stable across 1988-2012 with the only statistically significant increases in the 0-79 age group observed in Eastern Asia (AAPC: 1.8; 95% CI: 0.6, 1.9) and Sub-Saharan Africa (AAPC: 3.1; 95% CI: 0.5, 5.8). The small variation in incidence between regions and the stability in incidence over time suggests that OS carcinogenesis is not influenced by environmental or time-varying exposures.

Transcriptome-wide association studies increase the yield of loci associated with disease phenotypes by focusing on expression quantitative trait loci (eQTL). The major source of eQTL data for is the Gene and Tissue Expression (GTEx) project, which is comprised entirely of adults, mainly those &gt;50 years of age at death. Since gene expression levels differ by developmental stage, it is not clear whether eQTLs derived from adult data sources are best suited for use in young-onset diseases such as pediatric cancers. To fill in this knowledge gap, we performed a large-scale eQTL mapping analysis in the GenCord study with newborn samples and compared it with GTEx. Under matched conditions, we found around 80% of the eQTLs in one study can be replicated in the other. However, among all eQTLs identified in GenCord (GTEx), 584 (1045) showed statistically significant differences in effect sizes in GTEx (GenCord). We further investigated how using fetal eQTL data can facilitate the genetic association study of acute lymphoblastic leukemia. GenCord and GTEx identified the same genetic loci with statistical significance; however, the overall association pattern was only weakly correlated. Our paper demonstrates age-differential eQTLs and shows their potential influence on childhood leukemia research.

Background: Incidence rates of pediatric cancers in the United States are typically reported in 5-year age groups, obscuring variation by single year of age. Additionally, racial and ethnic variation in incidence is typically presented in broad categories rather than by narrow age ranges. Methods: The Surveillance, Epidemiology, and End Results (SEER) 18 data (2000-2017) were examined to calculate frequencies and age-adjusted incidence rates among individuals aged birth to 39 years. Incidence rate ratios (IRRs) and 95% confidence intervals (95% CIs) were estimated as the measure of association for rate comparisons by race and Hispanic origin overall and by single year of age. Results: Several histologic types showed substantial variation in race/ethnicity-specific and overall rates by single year of age. Overall, Black children and young adults experienced substantially decreased incidence of acute lymphoid leukemia (IRR, 0.52; 95% CI, 0.49-0.55) compared to Whites, and this decreased incidence was strongest at ages 1 through 7 years and 16 through 20 years. Hispanic individuals experienced decreased overall incidence of Hodgkin lymphoma (IRR, 0.50; 95% CI, 0.48-0.52) and astrocytoma (IRR, 0.54; 95% CI, 0.52-0.56) and increased risk of acute lymphoblastic leukemia (IRR, 1.46; 95% CI, 1.42-1.51) compared to non-Hispanic Whites, and the increased risk was strongest at ages 10 through 23 years. Substantial decreased risk across many tumor types was also observed for Asian/Pacific Islanders and American Indian/Alaska Natives. Conclusions: Examination of incidence rates for pediatric cancers by narrow age groups may provide insights regarding etiological differences in subgroups. Additionally, variation in age-specific incidence rates by race and ethnicity may enable hypothesis generation on drivers of disparities observed.

Graft-versus-host-disease (GVHD) is a multistep process that involves T-cell recognition and priming toward alloantigen, expansion, acquisition of effector function, and repeated tissue injury, resulting in clinical manifestations of the disease. All of these processes have considerable metabolic demands and understanding the key role of mitochondria in cellular metabolism as it relates to GVHD has increased significantly. Mitochondrial DNA (mtDNA) haplotypes have been linked to functional differences in vitro, suggesting they have functional differences at an organismal level. We previously used mtDNA typing to assess the impact of mtDNA haplotypes on outcomes of ~400 allo-HCT patients. This pilot study identified uncommon mtDNA haplotypes potentially associated with inferior outcomes. We sought to validate pilot findings of associations between donor and recipient mitochondrial haplotypes and transplant outcome. We examined a cohort of 4143 donor-recipient pairs obtained from the Center for International Blood and Marrow Transplant Research. MtDNA was extracted from whole blood or peripheral blood mononuclear cells from donors and recipients and sequenced to discern haplotype. We used multiple regression analysis to examine the independent association of mtDNA haplotype with overall survival and grade III-IV acute GVHD (aGVHD) adjusting for known risk factors for poor transplant outcome. Neither recipient nor donor mtDNA haplotype reached groupwise significance for overall survival (P =.26 and .39, respectively) or grade III-IV aGVHD (P = .68 and.57, respectively). Adjustment for genomically determined ancestry in the subset of donor-recipient pairs for which this was available did not materially change results. We conclude that our original finding was due to chance in a small sample size and that there is essentially no evidence that mtDNA haplotype or haplotype mismatch contributes to risk of serious outcomes after allogeneic transplantation.

Background: Males < 40 years old are more likely to be diagnosed with and die from osteosarcoma (OS). The underlying mechanisms may depend on sex differences in immune response. Methods: We used SEER data to estimate survival differences between males and females aged < 40 years at OS diagnosis. In NCI TARGET-OS cases, we determined sex differences in gene expression, conducted Gene Set Enrichment Analysis (GSEA), and applied the LM22 signature to identify biologic sex differences. We compared sex differences in gene expression profiles in TARGET-OS to those observed in Sleeping Beauty (SB) transposon mutagenesis accelerated Trp53R270H-mutant mouse-OS and healthy adult osteoblasts. Results: Males had worse 17-year overall survival than females (SEER p < 0.0001). From 87 TARGET-OS cases, we observed 1018 genes and 69 pathways that differed significantly by sex (adjusted p < 0.05). Pathway and gene lists overlapped with those from mice (p = 0.03) and healthy osteoblasts (p = 0.017), respectively. Pathways that differed significantly by sex were largely immune-based and included the PD-1/PD-L1 immunotherapy pathway. We observed sex differences in M2 macrophages (LM22; p = 0.056) and M1-M2 macrophage transition (GSEA; p = 0.037) in TARGET-OS. LM22 trends were similar in mice. Twenty-four genes differentially expressed by sex in TARGET-OS had existing cancer therapies. Conclusions: Sex differences in OS gene expression were similar across species and centered on immune pathways. Identified sex-specific therapeutic targets may improve outcomes in young individuals with OS.

Osteosarcoma has a guarded prognosis. A major hurdle in developing more effective osteosarcoma therapies is the lack of disease-specific biomarkers to predict risk, prognosis, or therapeutic response. Exosomes are secreted extracellular microvesicles emerging as powerful diagnostic tools. However, their clinical application is precluded by challenges in identifying disease-associated cargo from the vastly larger background of normal exosome cargo. We developed a method using canine osteosarcoma in mouse xenografts to distinguish tumor-derived from host-response exosomal mRNAs. The model allows for the identification of canine osteosarcoma-specific gene signatures by RNA sequencing and a species-differentiating bioinformatics pipeline. An osteosarcoma-associated signature consisting of five gene transcripts ( SKA2, NEU1, PAF1, PSMG2, and NOB1 ) was validated in dogs with spontaneous osteosarcoma by qRT-PCR, while a machine learning model assigned dogs into healthy or disease groups. Serum/plasma exosomes were isolated from 53 dogs in distinct clinical groups (“healthy”, “osteosarcoma”, “other bone tumor”, or “non-neoplastic disease”). Pre-treatment samples from osteosarcoma cases were used as the training set and a validation set from post-treatment samples was used for testing, classifying as “osteosarcoma–detected” or “osteosarcoma–NOT detected”. Dogs in a validation set whose post-treatment samples were classified as “osteosarcoma–NOT detected” had longer remissions, up to 15 months after treatment. In conclusion, we identified a gene signature predictive of molecular remissions with potential applications in the early detection and minimal residual disease settings. These results provide proof-of-concept for our discovery platform and its utilization in future studies to inform cancer risk, diagnosis, prognosis, and therapeutic response. ### Competing Interest Statement The authors declare that patent Identifying Presence and Composition of Cell Free Nucleic Acids, related to this work and listing Milcah C. Scott, John R. Garbe, and Jaime F. Modiano as inventors has been filed by the Office of Technology Commercialization of the University of Minnesota. US Patent Application 15/783,776 filed on October 13, 2017 The authors declare that patent Biological Status Determination Using Cell-Free Nucleic Acids, related to this work and listing Kelly M. Makielski, Alicia J. Donnelly, Ali Khammanivong, Milcah C. Scott, Hiro Tomiyasu, and Jaime F. Modiano as inventors has been filed by the Office of Technology Commercialization of the University of Minnesota. US Patent Application 16/600,486 filed on October 12, 2019

Background: Previous studies of mortality among patients with history of congenital heart surgery (CHS) have relied on underlying cause of death (UCOD), which may underestimate the impact of contributing causes of death.