Effect of parental adverse childhood experiences on intergenerational DNA methylation signatures from peripheral blood mononuclear cells and buccal mucosa

In this study, the effect of cumulative ACEs experienced on human maternal DNA methylation (DNAm) was estimated while accounting for interaction with domains of ACEs in prenatal peripheral blood mononuclear cell samples from the Maternal and Developmental Risks from Environmental Stressors (MADRES) pregnancy cohort. The intergenerational transmission of ACE-associated DNAm was also explored used paired maternal (N = 120) and neonatal cord blood (N = 69) samples. Replication in buccal samples was explored in the Children's Health Study (CHS) among adult parental (N = 31) and pediatric (N = 114) samples. We used a four-level categorical indicator variable for ACEs exposure: none (0 ACEs), low (1-3 ACEs), moderate (4-6 ACEs), and high (>6 ACEs). Effects of ACEs on maternal DNAm (N = 240) were estimated using linear models. To evaluate evidence for intergenerational transmission, mediation analysis (N = 60 mother-child pairs) was used. Analysis of maternal samples displayed some shared but mostly distinct effects of ACEs on DNAm across low, moderate, and high ACEs categories. CLCN7 and PTPRN2 was associated with maternal DNAm in the low ACE group and this association replicated in the CHS. CLCN7 was also nominally significant in the gene expression correlation analysis among maternal profiles (N = 35), along with 11 other genes. ACE-associated methylation was observed in maternal and neonatal profiles in the COMT promoter region, with some evidence of mediation by maternal COMT methylation. Specific genomic loci exhibited mutually exclusive maternal ACE effects on DNAm in either maternal or neonatal population. There is some evidence for an intergenerational effect of ACEs, supported by shared DNAm signatures in the COMT gene across maternal-neonatal paired samples.

Effect of Parental Adverse Childhood Experiences on Intergenerational DNA Methylation Signatures

Adverse Childhood Experiences (ACEs) are events that occur before a child turns 18 years old that may cause trauma. In this study, the effect of cumulative ACEs experienced on human maternal DNA methylation (DNAm) was estimated while accounting for interaction with domains of ACEs in prenatal peripheral blood mononuclear cell samples from the Maternal and Developmental Risks from Environmental Stressors (MADRES) pregnancy cohort. The intergenerational transmission of ACE-associated DNAm was also explored used paired maternal and neonatal cord blood samples. Replication in buccal samples was explored in the Children's Health Study (CHS). We used a four-level categorical indicator variable for ACEs exposure: none (0 ACEs), low (1-3 ACEs), moderate (4-6 ACEs), and high (> 6 ACEs). Effects of ACEs on maternal DNAm (N = 240) were estimated using linear models. To evaluate evidence for intergenerational transmission, mediation analysis was used. Analysis of maternal samples displayed some shared but mostly distinct effects of ACEs on DNAm across low, moderate, and high ACEs categories. CLCN7 and PTPRN2 was associated with maternal DNAm in the low ACE group and this association replicated in the CHS. ACE-associated methylation was observed in maternal and neonatal profiles in the COMT promoter region, with some evidence of mediation by maternal COMT methylation. Specific genomic loci exhibited mutually exclusive maternal ACE effects on DNAm in either maternal or neonatal population. There is some evidence for an intergenerational effect of ACEs, supported by shared DNAm signatures in the COMT gene across maternal-neonatal paired samples.

Meta-Analysis of DNA Methylation Datasets Shows Aberrant DNA Methylation of Thyroid Development or Function Genes in Down Syndrome

Background: In Down syndrome (DS), there is high occurrence of congenital hypothyroidism (CH) and subclinical hypothyroidism (SH) early in life. The etiology of CH and early SH in DS remains unclear. Previous research has shown genome-wide transcriptional and epigenetic alterations in DS. Thus, we hypothesized that CH and early SH could be caused by epigenetically driven transcriptional downregulation of thyroid-related genes, through promoter region hypermethylation. Methods: We extracted whole blood DNA methylation (DNAm) profiles of DS and non-DS individuals from four independent Illumina array-based datasets (252 DS individuals and 519 non-DS individuals). The data were divided into discovery and validation datasets. Epigenome-wide association analysis was performed using a linear regression model, after which we filtered results for thyroid-related genes. Results: In the discovery dataset, we identified significant associations for DS in 18 thyroid-related genes. Twenty-one of 30 significant differentially methylated positions (DMPs) were also significant in the validation dataset. A meta-analysis of the discovery and validation datasets detected 31 DMPs, including 29 promoter-associated cytosine-guanine dinucleotides (CpG) with identical direction of effect across the datasets, and two differentially methylated regions. Twenty-seven DMPs were hypomethylated and promoter associated. The mean methylation difference of hypomethylated thyroid-related DMPs decreased with age. Conclusions: Contrary to our hypothesis of generalized hypermethylation of promoter regions of thyroid-related genes-indicative of epigenetic silencing of promoters and subsequent transcriptional downregulation, causing biochemical thyroid abnormalities in DS-we found an enrichment of hypomethylated DMPs annotated to promoter regions of these genes. This suggests that CH and early SH in DS are not caused by differential methylation of thyroid-related genes. Considering that epigenetic regulation is dynamic, we hypothesize that the observed thyroid-related gene DNAm changes could be a rescue phenomenon in an attempt to ameliorate the thyroid phenotype, through epigenetic upregulation of thyroid-related genes. This hypothesis is supported by the finding of decreasing methylation difference of thyroid-related genes with age. The prevalence of early SH declines with age, so hypothetically, epigenetic upregulation of thyroid-related genes also diminishes. While this study provides interesting insights, the exact origin of CH and early SH in DS remains unknown.

Medulloblastoma uses GABA transaminase to survive in the cerebrospinal fluid microenvironment and promote leptomeningeal dissemination

Medulloblastoma (MB) is a malignant pediatric brain tumor arising in the cerebellum. Although abnormal GABAergic receptor activation has been described in MB, studies have not yet elucidated the contribution of receptor-independent GABA metabolism to MB pathogenesis. We find primary MB tumors globally display decreased expression of GABA transaminase (ABAT), the protein responsible for GABA metabolism, compared with normal cerebellum. However, less aggressive WNT and SHH subtypes express higher ABAT levels compared with metastatic G3 and G4 tumors. We show that elevated ABAT expression results in increased GABA catabolism, decreased tumor cell proliferation, and induction of metabolic and histone characteristics mirroring GABAergic neurons. Our studies suggest ABAT expression fluctuates depending on metabolite changes in the tumor microenvironment, with nutrient-poor conditions upregulating ABAT expression. We find metastatic MB cells require ABAT to maintain viability in the metabolite-scarce cerebrospinal fluid by using GABA as an energy source substitute, thereby facilitating leptomeningeal metastasis formation.

Adult diffuse glioma GWAS by molecular subtype identifies variants in D2HGDH and FAM20C

BACKGROUND

Twenty-five germline variants are associated with adult diffuse glioma, and some of these variants have been shown to be associated with particular subtypes of glioma. We hypothesized that additional germline variants could be identified if a genome-wide association study (GWAS) were performed by molecular subtype.

METHODS

A total of 1320 glioma cases and 1889 controls were used in the discovery set and 799 glioma cases and 808 controls in the validation set. Glioma cases were classified into molecular subtypes based on combinations of isocitrate dehydrogenase (IDH) mutation, telomerase reverse transcriptase (TERT) promoter mutation, and 1p/19q codeletion. Logistic regression was applied to the discovery and validation sets to test for associations of variants with each of the subtypes. A meta-analysis was subsequently performed using a genome-wide P-value threshold of 5 × 10-8.

RESULTS

Nine variants in or near D-2-hydroxyglutarate dehydrogenase (D2HGDH) on chromosome 2 were genome-wide significant in IDH-mutated glioma (most significant was rs5839764, meta P = 2.82 × 10-10). Further stratifying by 1p/19q codeletion status, one variant in D2HGDH was genome-wide significant in IDH-mutated non-codeleted glioma (rs1106639, meta P = 4.96 × 10-8). Further stratifying by TERT mutation, one variant near FAM20C (family with sequence similarity 20, member C) on chromosome 7 was genome-wide significant in gliomas that have IDH mutation, TERT mutation, and 1p/19q codeletion (rs111976262, meta P = 9.56 × 10-9). Thirty-six variants in or near GMEB2 on chromosome 20 near regulator of telomere elongation helicase 1 (RTEL1) were genome-wide significant in IDH wild-type glioma (most significant was rs4809313, meta P = 2.60 × 10-10).

CONCLUSIONS

Performing a GWAS by molecular subtype identified 2 new regions and a candidate independent region near RTEL1, which were associated with specific glioma molecular subtypes.

Outdoor artificial light at night and risk of non-Hodgkin lymphoma among women in the California Teachers Study cohort

BACKGROUND

Outdoor artificial light at night (ALAN) has been implicated in a growing number of adverse health outcomes. ALAN is believed to disrupt circadian rhythms and has been associated with increased inflammation, one of the hallmarks of cancer. We examined the association between outdoor ALAN and a cancer strongly associated with autoimmune and inflammatory conditions, non-Hodgkin lymphoma (NHL), in the prospective California Teachers Study cohort.

METHODS

Outdoor ALAN was assigned to participant addresses at study baseline (1995-96) through use of the New World Atlas of Artificial Night Sky Brightness. Among 105,937 women followed from 1995 to 2015, linkage to the California Cancer Registry identified 873 incident cases of NHL. Age-stratified Cox proportional hazards models were used to calculate hazard ratios (HR) and 95 % confidence intervals (95 %CI) for overall NHL and the most common NHL subtypes; diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL) and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Multivariate analyses adjusted for previously reported subtype specific covariates (e.g. body mass index (BMI) for DLBCL).

RESULTS

Compared to the lowest quintile, participants residing in the highest quintile of outdoor ALAN at baseline were more likely to develop NHL (HR = 1.32, 95 %CI = 1.07-1.63), and, in particular, DLBCL (HR = 1.87, 95 %CI = 1.16-3.02). The elevated risk for DLBCL remained statistically significant after adjusting for age, race/ethnicity, BMI, and socioeconomic status (DLBCL:HR = 1.87, 95 %CI = 1.16-3.02, NHL:HR = 1.32, 95 %CI = 1.07-1.63). There was no association between ALAN and FL or CLL/SLL.

CONCLUSION

DLBCL risk was elevated among women residing in neighborhoods with greater outdoor ALAN. Future research in circadian disruption and DLBCL may clarify potential biological processes implicated in this association.

Abstract PO-125: Prenatal proximity to agricultural use of endocrine-disrupting pesticides and risk of testicular germ cell tumor (TGCT) among Latino and non-Latino adolescents in California

BACKGROUND. Incidence of testicular germ cell tumors (TGCTs) has increased steadily in the United States in recent years, especially among Latinos. TGCT initiation is believed to occur during fetal development and to be related to endocrine disruption; the increasing prevalence of in utero exposures to endocrine- disrupting chemicals may have contributed to the rise in the disease’s incidence.

METHODS. This registry-based case-control study included 381 California-born patients diagnosed with TGCT at age 15-19 years from 1997-2011 (336 non- seminomas, 41 seminomas) and 762 controls matched on birth year and race/ethnicity. We assessed the agricultural application of 22 endocrine-disrupting pesticides (EDPs) using California’s Pesticide Use Reporting (PUR) database for an area within a 3km radius of participants’ birth address in the year prior to birth; 15 high-volume EDPs (those to which 50 or more participants were potentially exposed) were included in statistical analyses. We used logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for log2-transformed continuous pesticide levels, and to calculate attributable risk (AR) for dichotomous exposure (zero and low application vs. high application). Analyses accounted for the timing of pesticide application, histologic subtype, race/ethnicity, birth year, and neighborhood socioeconomic status (SES). RESULTS. Overall, 48% of cases and 45% of controls lived within 3km of an EDP application in the year before birth. Nearby pesticide applications were greater among Latinos than non-Latinos for 13 of 15 EDPs; the median [interquartile range (IQR)] for total EDP application was 29 kg [5- 135] vs. 11 kg [1-80]. Application was also greater for those born after 1990 (the period of time with complete PUR reporting) than before 1990 for 14 of 15 EDPs (median [IQR] for total EDP application: 54 kg [10-229] vs. 13 kg [0.7-70]). Analyses of individual EDPs showed an increased risk of TGCT associated with acephate (OR [95%CI]: 1.1 [1.0-1.2] and 1.3 [1.0-1.7] for continuous and binary exposures, respectively). In analyses stratified by ethnicity, risk remained elevated for acephate application among Latinos (n=614, OR [95% CI] for continuous exposure model: 1.1 [1.0-1.2]) and for carbaryl and copper sulfate in non-Latinos (n=504, OR [95% CI]: 1.2 [1.0-1.3] and 1.1 [1.0-1.3], respectively). Overall there were no differences by PUR reporting period (before and after 1990) and application timing (preconception and trimesters), yet risk appeared to be higher for non-seminomas and among high SES participants. The population AR for high levels of acephate was 5.4% among Latinos, and <1% prior to 1990 vs. 10% after 1990 for all subjects combined. In non-Latinos, the AR for carbaryl was 4.8% and 2.5% for copper sulfate. CONCLUSIONS. Acephate, an organophosphate insecticide, was associated with an increased TGCT risk, possibly contributing 5-10% to the prevalence of TGCT among Latinos in California.

Citation Format: Scott J. Swartz, Libby Morimoto, Todd Whitehead, Robert Gunier, Joseph Wiemels, Xiaomei Ma, Catherine Metayer. Prenatal proximity to agricultural use of endocrine-disrupting pesticides and risk of testicular germ cell tumor (TGCT) among Latino and non-Latino adolescents in California [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-125.

Abstract 1193: Adult diffuse glioma GWAS by molecular subtype identifies variants in D2HGDH, FAM20C and GMEB2

Background: Genome-wide association studies (GWAS) revealed that 25 regions in 24 genes are associated with adult diffuse glioma development. These regions were identified by performing GWAS of glioma overall and by pathology (GBM and nonGBM). The 2016 WHO Classification of Tumors of the Central Nervous System utilizes two somatic alterations to molecularly-classify adult diffuse glioma: IDH mutation and 1p/19q codeletion. We hypothesized that germline variants may increase susceptibility to, or interact with, these somatic alterations to accelerate the development of specific molecular subtypes of glioma. We further hypothesize that germline variants associated with IDH-mutated glioma might be associated with other IDH-mutated tumors, namely, cholangiocarcinoma, acute myeloid leukemia (AML) and melanoma.

Methods: We performed a GWAS by glioma molecular subtype - as defined by presence or absence of IDH somatic mutation and 1p/19q codeletion. A total of 1320 glioma cases and 1889 controls were used in the discovery set, and 799 glioma cases and 808 controls in the validation set. A meta-analysis was performed with a genome-wide p-value threshold of 5 × 10−8. GTEx data were used to perform an expression quantitative trait loci (eQTL) analysis. For germline variants that were significantly associated with IDH-mutated glioma, we evaluated pleiotropy with cholangiocarcinoma, AML and melanoma using TCGA and Mayo Biobank controls.

Results: Variants in or near D2HGDH on chromosome 2 were genome-wide significant in IDH-mutated glioma (meta p-value = 2.82 × 10−10). TCGA reported that the D2HGDH region was commonly deleted in IDH-mutated gliomas that do not have 1p/19q codeletion. In TCGA data for IDH-mutated, non-codeleted glioma, we observed that the D2HGDH variant was inversely associated with tumor deletions of D2HGDH (odds ratio=0.57, p-value=0.015). The eQTL analyses demonstrated significant associations between D2HGDH germline variant and expression of D2HGDH (p=2.2 × 10−11). Further stratifying IDH-mutated glioma by 1p/19q codeletion status, one variant near FAM20C on chromosome 7 was genome-wide significant in gliomas that have IDH mutation and 1p/19q codeletion (meta p-value=9.56 × 10−9). Analyses are currently underway to evaluate pleiotropy of these IDH-mutated glioma germline variants with other IDH-mutated tumors including cholangiocarcinoma, AML and melanoma. Variants in or near GMEB2 on chromosome 20 were genome-wide significant in IDH wild-type glioma (meta p-value=2.60 × 10−10). The most significant variant in the GMEB2 region remained significant after adjustment for the known RTEL1 glioma risk variant nearby on chromosome 20 (p=0.029).

Conclusions: We identified and validated novel germline variants in two genes that are associated with etiology of IDH-mutated and one gene that is associated with IDH wild-type adult diffuse glioma.

Citation Format: Jeanette E. Eckel-Passow, Kristen L. Drucker, Thomas M. Kollmeyer, Matthew L. Kosel, Paul A. Decker, Annette M. Molinaro, Terri Rice, Corrine E. Praska, Lauren E. Clark, Alissa A. Caron, Alexej Abyzov, Anthony Batzler, Jun S. Song, Melike Pekmezci, Helen M. Hansen, Lucie S. McCoy, Paige M. Bracci, Joseph Wiemels, John K. Wiencke, Stephen Francis, Terence C. Burns, Caterina Giannini, Daniel H. Lachance, Margaret Wrensch, Robert B. Jenkins. Adult diffuse glioma GWAS by molecular subtype identifies variants in D2HGDH, FAM20C and GMEB2 [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1193.

Abstract A105: Trends in acute lymphocytic leukemia (ALL) incidence in the US from 2000-2016

Objectives. The causes of ALL are determined in part by genetic factors but less clear is the role of the environment. Temporal and demographic changes in incidence may help illuminate causes and help direct new lines of research. We sought to investigate in the US from 2000-2016, 1) the distribution of ALL incidence by race/ethnicity, 2) trend change in ALL incidence and 3) the association between ALL incidence and location of birth (US or a foreign country) among different ages and race/ethnicity groups. Methods. We used data from the population-based Surveillance, Epidemiology and End Results (SEER) Registry. Age-adjusted incidence rates (AAIRs) per 100,000 persons were calculated for people of Latino ethnicity (all races), Non-Latino (NL) White, NL Black, NL Asian and Pacific Islander (API), NL American Indian, and Alaskan Native (AIAN). Trends of ALL from 2000 to 2016 were evaluated with the annual percent change (APC) of AAIRs. We further used a Poisson regression model with standardized population offset to analyze the association between the community-level percent of people born in a foreign country and the AAIR of ALL among NL Whites, NL Blacks, and Latinos. The analyses were stratified by race/ethnicity and age groups, and adjusted for sex, year of diagnosis and socioeconomic position (SEP, identified with a time-dependent Yost index variable from census tract). Results. Among 23,829 individuals of all ages diagnosed with ALL from 2000 to 2016 in the US, 8,297 were Latinos, 11,714 were NL Whites, and 1,639 were non-Latino Blacks. Compared to NL Whites (AAIR=1.56), the AAIR was significantly higher for Latinos (AAIR=2.43; p<.001) but lower for NL Blacks (AAIR=0.95; p<.001). The AAIR increased significantly from 2000-2016 overall (APC=0.97; 95% CI:0.67, 1.27), with the highest increase in Latinos (APC=1.18; 95% CI: 0.76, 1.60). The AAIR for NL Whites, APIs, and AIANs remained stable during the study period. In adjusted models, AAIRs increased significantly with the percent of foreign-born for NL Whites (p-trend<.001) and Blacks (p-trend<.001), but decreased with the percent of foreign-born for Latinos (p-trend<.001). This finding was consistent for all age groups. Conclusion. The Age Adjusted Incidence Rates (AAIRs) of ALL from 2000-2016 were highest among Latinos compared to other ethnic groups. Latinos had the fastest increase in AAIR in this period, which was significant in the childhood, young adult, and older adult age groups. Our analysis showed several intriguing trends relating to ethnicity and country of origin which remain unexplained in the scientific literature. Most notably, we show that previously-noted increases in the incidence of ALL for Latinos have continued to climb, in both children and adults, establishing this group as the most highly burdened with this disease. These trends should help direct future research into risk identification and disease prevention in the most vulnerable populations.

Citation Format: Qianxi Feng, Maria Vergara-Lluri, Ivo Muskens, Roberta McKean-Cowdin, Scott Kogan, Russell Brynes, Adam de Smith, Joseph Wiemels. Trends in acute lymphocytic leukemia (ALL) incidence in the US from 2000-2016 [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr A105.

0383 Outdoor Artificial Light at Night, Sleep Duration, and Sleep Quality in the California Teachers Study Cohort

Introduction

Artificial light at night (ALAN) is believed to disrupt sleep by suppressing melatonin and altering normal circadian patterns. We assessed the association between self-reported sleep measures and outdoor ALAN in a large cohort of women.

Methods

The California Teachers Study (CTS) is a prospective cohort of 133,479 current and former Californian female public school professionals recruited and given a baseline questionnaire in 1995-1996. A follow-up questionnaire in 2012-2014 assessed self-reported measures of sleep habits, quality, and chronotype. Using geocoded residential addresses, participants were assigned exposures to outdoor ALAN based on the New World Atlas of Artificial Night Sky Brightness to assess the association between ALAN and self-reported sleep initiation, duration, and quality.

Results

Of the 42,706 women who completed the follow-up questionnaire and reported the same sleep patterns over the previous year, 5,968 reported poor sleep quality. The median outdoor ALAN was 2.16 (IQR: 1.04-3.61) millicandela per meter squared (mcd/m2). After adjusting for self-reported chronotype, use of sleep medication, age, race, and socioeconomic status, residing in the highest ALAN quintile was associated with poor sleep (OR 1.16, 95% CI 1.07-1.26). There did not appear to be an association between outdoor ALAN and time taken to fall asleep (OR 1.02, 95% CI 0.96-1.08), but it was associated with sleeping less than 8 hours (OR 1.41, 95% CI 1.33-1.50).

Conclusion

CTS participants who self-reported shorter sleep and poorer sleep quality were more likely to reside in areas with greater levels of outdoor ALAN. We did not see an association with ALAN and time to fall asleep, suggesting ALAN may be contributing to later sleep time or earlier waking. As we continue to follow this cohort, the data collected over the past 20 years provide a rich resource for studying both factors related to sleep and its effect on health.

Support

The California Teachers Study and the research reported in this publication were supported by the National Cancer Institute of the National Institutes of Health under award number U01-CA199277; P30-CA033572; P30-CA023100; UM1-CA164917; R01-CA077398; and R01-CA207020.

PDTM-33. EUROPEAN GENETIC ANCESTRY ASSOCIATED WITH RISK OF CHILDHOOD EPENDYMOMA

BACKGROUND

Ependymoma is a histologically-defined central nervous system tumor most commonly occurring in children. Incidence differs by race/ethnicity, with individuals of European ancestry at highest risk. No large-scale genomic analyses of ependymoma predisposition have been conducted to date. We aimed to determine whether extent of European genetic ancestry is associated with ependymoma risk.

METHODS

In a multi-ethnic study of Californian children (327 cases, 1970 controls), we estimated the proportions of European, African, and Native American ancestry among admixed Hispanic and African-American subjects and estimated European substructure among non-Hispanic white subjects using genome-wide data. We tested whether genome-wide ancestry differences were associated with ependymoma risk and performed admixture mapping to identify associations with local European ancestry. We also re-analyzed CBTRUS data to examine subtype-specific differences in ependymoma incidence across racial/ethnic groups.

RESULTS

Each 20% increase in European ancestry was associated with 1.31-fold greater odds of ependymoma among Hispanic and African-American subjects (95% CI: 1.08–1.59, Pmeta=6.7×10–3). Among non-Hispanic whites, European ancestral substructure was also significantly associated with ependymoma risk. Local admixture mapping revealed a peak at 20p13 associated with increased local European ancestry, and genotype association analysis in the region identified an association upstream of R-spondin 4 that survived Bonferroni correction (P=2.2x10-5) but was not validated in an independent set of posterior fossa type A (PF-EPN-A) patients. In complementary CBTRUS analyses, American Indian/Alaskan Natives were at reduced risk relative to non-Hispanic whites (RR=0.64, 95% CI:0.46–0.87), as were African-Americans (RR=0.67, 95% CI:0.60–0.74) and Asian/Pacific Islanders (RR=0.86, 95% CI:0.73–1.00). Although overall ependymoma rates were similar in U.S. Hispanics (RR=0.96, 95% CI:0.88–1.05), lower rates were observed for myxopapillary ependymoma and other spinal ependymoma.

CONCLUSION

Inter-ethnic differences in ependymoma risk vary by histopathologic and potentially molecular subgroup, and are recapitulated in the genomic ancestry of ependymoma patients.

MNGI-12. PLEIOTROPIC MLLT10 VARIATION CONFERS RISK OF MENINGIOMA, BREAST, AND OVARIAN CANCERS

BACKGROUND

Women ages 35–44 have three-fold higher risk of meningioma compared to men. Epidemiologic studies have implicated exogenous hormone use, but endogenous hormonal factors are inconsistently associated. Elevated body mass index (BMI) is consistently associated with meningioma risk in both men and women, and personal history of breast cancer has also been associated with meningioma risk. Recent genome-wide association studies (GWAS) have identified a meningioma risk locus on chromosome 10p12 near previous GWAS hits for breast and ovarian cancers.

METHODS

To elucidate the pleiotropic role of 10p12 variation in predisposition to diverse tumors - possibly via a common mediating factor - we performed imputation‐based fine‐mapping in three case-control datasets of meningioma (927 cases, 790 controls), female breast cancer (28108 cases, 22209 controls), and ovarian cancer (25509 cases, 40941 controls). Analyses were stratified by sex (meningioma), estrogen receptor status (breast), and histotype (ovarian), then combined using ASSET meta-analysis. Lead variants were queried for association with >700 additional traits to identify potential effect-mediators.

RESULTS

Two-sided ASSET meta-analysis identified a lead variant near the MLLT10 promoter (P=1.4x10-13) associated with significantly increased risk of meningioma in women (OR=1.42, 95% CI: 1.20–1.69) and non-significantly increased risk in men (OR=1.19, 95% CI: 0.91–1.57). The meningioma risk allele was also associated with ovarian cancer risk (OR=1.09, 95% CI: 1.06–1.12) and ER+ breast cancer risk (OR=1.05, 95% CI: 1.02–1.08), but protected against ER- breast cancer (OR=0.91, 95% CI: 0.86–0.96). The risk allele was associated with higher body fat percentage, waist circumference and BMI at genome-wide levels (P< 5.0x10-8), but mediation analysis adjusting for BMI did not attenuate its association with meningioma risk.

CONCLUSION

We identify a MLLT10 eQTL that confers risk of female meningioma, ER+ breast cancer, ovarian cancer, and obesity, but which protects against ER- breast cancer. Our results implicate a possible estrogenic mechanism underlying meningioma tumorigenesis.

GENE-25. GWAS BY MOLECULAR SUBTYPE IDENTIFIED NOVEL RISK LOCI FOR ADULT DIFFUSE GLIOMA

Genome-wide association studies (GWAS) have revealed that 25 regions in 24 genes are associated with adult diffuse glioma development. These regions were identified by performing GWAS of glioma overall and GWAS by pathology (GBM and nonGBM). Subsequently, these regions have been evaluated for associations with specific molecular subtypes. The 2016 WHO Classification of Tumors of the Central Nervous System utilizes two somatic alterations to molecularly-classify adult diffuse glioma: IDH mutation and 1p/19q codeletion. TERT promoter mutation has also been shown to be associated with age at diagnosis and patient outcome. We hypothesized that germline variants may increase susceptibility to, or interact with, these somatic alterations to accelerate the development of specific molecular subtypes of glioma. To test our hypothesis, we performed a GWAS by glioma molecular subtype – as defined by presence or absence of IDH and TERT somatic mutation and 1p/19q codeletion – utilizing a two-stage design and subsequent meta analysis that included 3001 total glioma cases and 2697 total controls. Data were imputed using the Michigan Server and logistic regression was used, adjusting for age and sex. The Cancer Genome Atlas (TCGA) data were used to perform an expression quantitative trait loci (eQTL) analysis on candidate germline variants. Variants in 2q37 and 7p22 were associated with IDH-mutated glioma (meta analysis p< 5x10-8). The eQTL analyses demonstrated significant associations between 2q37 variants and expression of nearby genes as well as associations between 7p22 variants and nearby genes (p< 0.0001). In conclusion, we identified and validated novel germline variants in two genes that are associated with etiology of IDH-mutated adult diffuse glioma.

Meta-analysis of epigenome-wide association studies in neonates reveals widespread differential DNA methylation associated with birthweight

Birthweight is associated with health outcomes across the life course, DNA methylation may be an underlying mechanism. In this meta-analysis of epigenome-wide association studies of 8,825 neonates from 24 birth cohorts in the Pregnancy And Childhood Epigenetics Consortium, we find that DNA methylation in neonatal blood is associated with birthweight at 914 sites, with a difference in birthweight ranging from -183 to 178 grams per 10% increase in methylation (PBonferroni < 1.06 x 10-7). In additional analyses in 7,278 participants, <1.3% of birthweight-associated differential methylation is also observed in childhood and adolescence, but not adulthood. Birthweight-related CpGs overlap with some Bonferroni-significant CpGs that were previously reported to be related to maternal smoking (55/914, p = 6.12 x 10-74) and BMI in pregnancy (3/914, p = 1.13x10-3), but not with those related to folate levels in pregnancy. Whether the associations that we observe are causal or explained by confounding or fetal growth influencing DNA methylation (i.e. reverse causality) requires further research.

Epigenomic profiling of newborns with isolated orofacial clefts reveals widespread DNA methylation changes and implicates metastable epiallele regions in disease risk

Cleft lip with or without cleft palate (CL/P) is a common human birth defect whose etiologies remain largely unknown. Several studies have demonstrated that periconceptional supplementation of folic acid can reduce risk of CL/P in offspring. In this study, we tested the hypothesis that the preventive effect of folic acid is manifested through epigenetic modifications by determining whether DNA methylation changes are associated with CL/P. To more readily observe the potential effects of maternal folate on the offspring epigenome, we focused on births prior to mandatory dietary folate fortification in the United States (i.e. birth year 1997 or earlier). Genomic DNA methylation levels were assessed from archived newborn bloodspots in a 182-member case-control study using the Illumina® Human Beadchip 450K array. CL/P cases displayed striking epigenome-wide hypomethylation relative to controls: 63% of CpGs interrogated had lower methylation levels in case newborns, a trend which held up in racially stratified sub-groups. 28 CpG sites reached epigenome-wide significance and all were case-hypomethylated. The most significant CL/P-associated differentially methylated region encompassed the VTRNA2-1 gene, which was also hypomethylated in cases (FWER p = 0.014). This region has been previously characterized as a nutritionally-responsive, metastable epiallele and CL/P-associated methylation changes, in general, were greater at or near putative metastable epiallelic regions. Gene Set Enrichment Analysis of CL/P-associated DMRs showed an over-representation of genes involved in palate development such as WNT9B, MIR140 and LHX8. CL/P-associated DNA methylation changes may partly explain the mechanism by which orofacial clefts are responsive to maternal folate levels.

Abstract 3241: Children with acute lymphoblastic leukemia have increased arginase 2 at birth, implicating immunosuppression in leukemogenesis

Background: Epidemiologic evidence points to a role for infection and immune development in childhood acute lymphoblastic leukemia (ALL). Emerging evidence suggests that in utero immunosuppressive processes, along with immaturity at birth, cause immune hyporesponsiveness to commensal microbes and susceptibility to early childhood infections. A key regulator of active immunosuppression within the neonatal environment is arginase 2, which is produced by CD71+ erythroid cells and myeloid-derived suppressor cells. Arginase-dependent arginine depletion is suspected to aggravate both infections and tumor growth (the latter in adult settings) due to suppressed T-cell function by downregulation of TCR-CD3ζ. Studies have shown that immune vulnerability of the preterm neonate is critically related to arginase-dependent arginine depletion, but none have investigated this neonatal immunosuppression in relation to ALL.

Methods: Children were identified via California Cancer and Vital Statistics Registries, and their neonatal dried bloodspots derived from the California Genetic Disease Screening Program. Children were born in California between 1999 and 2009, with ALL cases being 0-15 years of age at diagnosis. 137 ALL cases and 500 controls (frequency matched on birthdate, gender, and ethnicity) were analyzed. Arginase 2 levels were measured using enzyme-linked immunosorbent assay (ELISA), with total serum-protein levels measured using the Pierce BCA protein assay. Arginase 2 levels in the analyses were adjusted for total serum protein and analyzed both as a continuous variable and as quartiles based on the distribution among controls. Adjusted unconditional logistic regression was used to estimate odds ratios (OR) for the association between neonatal arginase 2 and ALL with assay plate variance structure accounted for using cluster methods.

Results: Arginase 2 levels in neonatal dried blood spots were significantly higher among cases with ALL than controls (OR = 1.36, 95% CI: 1.02-1.80, p = 0.03). The highest quartile of arginase 2 levels differed significantly from the lowest (OR = 1.81, 95% CI: 1.04-3.41, p = 0.03), while the intermediate quartiles had a trend towards higher arginase 2 levels (p for trend: 0.02).

Conclusions: Our findings suggest that children with ALL have significantly higher immunosuppression at birth due to increased arginase 2. A high neonatal level of this enzyme, an important downregulator of T-cell activity, may lead to altered immune responses to antigenic stimulation and infection during early childhood and potentially impact the immune system's capability to react against nascent cancer. In addition to previously discovered prenatal mutations, this new finding of an immunosuppressed environment at birth contributes to our understanding of early events in the development of ALL.

Citation Format: Amalie B. Nielsen, Mi Zhou, Adam de Smith, Lucie McCoy, Helen Hansen, Paige Bracci, Libby Morimoto, Scott Kogan, Catherine Metayer, Xiaomei Ma, Joseph Wiemels. Children with acute lymphoblastic leukemia have increased arginase 2 at birth, implicating immunosuppression in leukemogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3241.

Abstract 1273: Pathway analysis of insulin-like growth factor candidate genes and risk of pediatric rhabdomyosarcoma

Pediatric rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children under 15 years of age. Due largely to its rarity, the etiology of pediatric RMS is poorly understood. Patterns of fetal growth were previously shown to be independent risk factors for RMS among non-Hispanic white (NHW) children; however, the underlying biologic mechanisms remain unclear. Alterations in the insulin-like growth factor (IGF) system, the primary regulator of growth during the fetal and early life period, may provide clues. Using an innovative linkage between the California birth records and cancer registry information, we conducted a population-based case-control study (1982-2009) of candidate genes involved in IGF signaling and risk of pediatric RMS. Fifteen genes involved in the IGF pathway were selected: IGF1, IGF2, IGF1R, IGF2R, IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, IGFBP6, INS, INSR, IRS1, GH1, and GHRH. DNA extracted from the archived newborn blood spots of all available RMS cases (n=644) was genotyped on the Illumina OmniExpress Exome array (n=964,043 SNPs); after stringent quality control (QC), a total of 633 RMS cases (360 embryonal RMS [eRMS] and 197 alveolar RMS [aRMS]) were available for analysis. A total of 815 controls genotyped on the Illumina OmniExpress Exome array and 3,922 controls genotyped on the Affymetrix Axion LAT array (n=801,830 SNPs) from the same base population of California children, with no evidence of RMS, were included in this analysis. After imputation to increase coverage of the genome and post-imputation QC to identify and remove platform effects, a total of 5,556,335 SNPs were available for analysis. Among NHW children, SNPs in IGF1 (rs10860869, p=0.0031) and IGF1R (rs62023616, p=0.00074; rs62023648, p=0.00076) were significantly associated with RMS risk after adjustment for multiple comparisons. Analyses stratified by histologic subtype showed that these associations were limited to eRMS, and of stronger magnitude. Among Hispanic children, 12 SNPs in IGF1R (p-value range: 0.0007-0.0027) and 3 SNPs in IGFBP1 (p-values: 0.0016-0.0023) were significantly associated with eRMS risk. The SNPs found to be associated with RMS were located in intergenic and intronic areas of the genes, areas that may influence gene regulation. Our results support the hypothesis that genetic variation in IGF1 signaling pathway modulate the risk of RMS, especially eRMS, among NHW and Hispanic children.

Citation Format: Libby Morimoto, XIaorong Shao, Anand Chokkalingam, Joseph Wiemels, Xiaomei Ma, Catherine Metayer. Pathway analysis of insulin-like growth factor candidate genes and risk of pediatric rhabdomyosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1273. doi:10.1158/1538-7445.AM2017-1273

Abstract 2263: Neonatal hormone levels and risk of testicular germ cell tumors (TGCT)

Testicular germ cell tumors (TGCT) are the most commonly occurring cancers in adolescent and young adult males in the U.S. Steroid sex hormones play a central role in the development of the testis. As proposed by the testicular dysgenesis syndrome hypothesis, the origins of TGCT are likely to be in utero or early in life, and to be a manifestation of disturbed prenatal testis development. However, no studies have provided direct, empirical evidence to date. Using an innovative linkage between the California birth records and cancer registry data, we conducted a population-based case-control study of neonatal hormones levels and risk of TGCT diagnosed at 0-19 year of age. We obtained archived neonatal dried blood spot (DBS) specimens from 370 TGCT cases (276 adolescent and young adults [AYA] aged 15-19 yrs at diagnosis; 94 0-4 yrs at diagnosis), and 344 age- and race/ethnicity-matched controls, born between 1982 and 2009. Liquid chromatography with tandem mass spectrometry was used to measure a panel of 17 sex steroids, glucocorticoids, and mineralcorticoids; 12 were present at detectable levels in the newborn DBS samples, including estrone (E1), estradiol (E2), estriol (E3), testosterone (T), dehydroepiandrosterone (DHEA), and androstenedione (A4). Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI), adjusting for matching factors and age (in hours) of child at blood spot collection. A4, a precursor for T and E1, was positively associated with TGCT (OR: 1.71, 95% CI: 1.09-2.69). Analyses stratified by age group showed that this association was limited to AYA, and was of stronger magnitude in this group (OR: 2.33, 95% CI: 1.37-3.97). A similar, though weaker, trend was observed for T (ORoverall: 1.37, 95% CI: 0.86-2.19; ORAYA: 1.73. 95% CI: 1.00-3.00). There was no significant association of the other measured hormones with risk. In the first case-control study of TGCT with direct measures of neonatal hormone levels, we found that higher levels of T and A4 were associated with increased risk of TCGT, particularly among males diagnosed at 15-19 years of age. These results oppose the dominant theory in TGCT etiology, that TGCT is related to androgen insufficiency in utero, and provides an important link in the etiologic pathway of this increasingly common cancer.

Citation Format: Libby Morimoto, David Zava, Katherine McGlynn, Frank Stanczyk, Joseph Wiemels, Xiaomei Ma, Catherine Metayer. Neonatal hormone levels and risk of testicular germ cell tumors (TGCT) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2263. doi:10.1158/1538-7445.AM2017-2263

Buccal mucosa micronuclei counts in relation to exposure to low dose-rate radiation from the Chornobyl nuclear accident and other medical and occupational radiation exposures

BACKGROUND

Ionizing radiation is a well-known carcinogen. Chromosome aberrations, and in particular micronuclei represent an early biological predictor of cancer risk. There are well-documented associations of micronuclei with ionizing radiation dose in some radiation-exposed groups, although not all. That associations are not seen in all radiation-exposed groups may be because cells with micronuclei will not generally pass through mitosis, so that radiation-induced micronuclei decay, generally within a few years after exposure.

METHODS

Buccal samples from a group of 111 male workers in Ukraine exposed to ionizing radiation during the cleanup activities at the Chornobyl nuclear power plant were studied. Samples were taken between 12 and 18 years after their last radiation exposure from the Chornobyl cleanup. The frequency of binucleated micronuclei was analyzed in relation to estimated bone marrow dose from the cleanup activities along with a number of environmental/occupational risk factors using Poisson regression adjusted for overdispersion.

RESULTS

Among the 105 persons without a previous cancer diagnosis, the mean Chornobyl-related dose was 59.5 mSv (range 0-748.4 mSv). There was a borderline significant increase in micronuclei frequency among those reporting work as an industrial radiographer compared with all others, with a relative risk of 6.19 (95% CI 0.90, 31.08, 2-sided p = 0.0729), although this was based on a single person. There was a borderline significant positive radiation dose response for micronuclei frequency with increase in micronuclei per 1000 scored cells per Gy of 3.03 (95% CI -0.78, 7.65, 2-sided p = 0.1170), and a borderline significant reduction of excess relative MN prevalence with increasing time since last exposure (p = 0.0949). There was a significant (p = 0.0388) reduction in MN prevalence associated with bone X-ray exposure, but no significant trend (p = 0.3845) of MN prevalence with numbers of bone X-ray procedures.

CONCLUSIONS

There are indications of increasing trends of micronuclei prevalence with Chornobyl-cleanup-associated dose, and indications of reduction in radiation-associated excess prevalence of micronuclei with time after exposure. There are also indications of substantially increased micronuclei associated with work as an industrial radiographer. This analysis adds to the understanding of the long-term effects of low-dose radiation exposures on relevant cellular structures and methods appropriate for long-term radiation biodosimetry.

Small-Magnitude Effect Sizes in Epigenetic End Points are Important in Children's Environmental Health Studies: The Children's Environmental Health and Disease Prevention Research Center's Epigenetics Working Group

BACKGROUND

Characterization of the epigenome is a primary interest for children's environmental health researchers studying the environmental influences on human populations, particularly those studying the role of pregnancy and early-life exposures on later-in-life health outcomes.

OBJECTIVES

Our objective was to consider the state of the science in environmental epigenetics research and to focus on DNA methylation and the collective observations of many studies being conducted within the Children's Environmental Health and Disease Prevention Research Centers, as they relate to the Developmental Origins of Health and Disease (DOHaD) hypothesis.

METHODS

We address the current laboratory and statistical tools available for epigenetic analyses, discuss methods for validation and interpretation of findings, particularly when magnitudes of effect are small, question the functional relevance of findings, and discuss the future for environmental epigenetics research.

DISCUSSION

A common finding in environmental epigenetic studies is the small-magnitude epigenetic effect sizes that result from such exposures. Although it is reasonable and necessary that we question the relevance of such small effects, we present examples in which small effects persist and have been replicated across populations and across time. We encourage a critical discourse on the interpretation of such small changes and further research on their functional relevance for children's health.

CONCLUSION

The dynamic nature of the epigenome will require an emphasis on future longitudinal studies in which the epigenome is profiled over time, over changing environmental exposures, and over generations to better understand the multiple ways in which the epigenome may respond to environmental stimuli.

Trends in childhood leukemia incidence over two decades from 1992 to 2013

Incidence rates of childhood leukemia in the United States have steadily increased over the last several decades, but only recently have disparities in the increase in incidence been recognized. In the current analysis, Surveillance, Epidemiology and End Results (SEER) data were used to evaluate recent trends in the incidence of childhood leukemia diagnosed at age 0-19 years from 1992 to 2013, overall and by age, race/ethnicity, gender and histologic subtype. Hispanic White children were more likely than non-Hispanic White, non-Hispanic Black or non-Hispanic Asian children to be diagnosed with acute lymphocytic leukemia (ALL) from 2009 to 2013. From 1992 to 2013, a significant increase in ALL incidence was observed for Hispanic White children [annual percent change (APC)Hispanic  = 1.08, 95% CI: 0.59, 1.58]; no significant increase was observed for non-Hispanic White, Black or Asian children. ALL incidence increased by about 3% per year from 1992 to 2013 for Hispanic White children diagnosed from 15 to 19 years (APC = 2.67; 95% CI: 0.88, 4.49) and by 2% for those 10-14 years (APC = 2.09; 95% CI: 0.57, 3.63), while no significant increases in incidence were observed in non-Hispanic White, Black, or Asian children of the same age. Acute myeloid leukemia (AML) incidence increased among non-Hispanic White children under 1 year at diagnosis, and among Hispanic White children diagnosed at age 1-4. The increase in incidence rates of childhood ALL appears to be driven by rising rates in older Hispanic children (10-14, and 15-19 years). Future studies are needed to evaluate reasons for the increase in ALL among older Hispanic children.

Association of common genetic variation in the protein C pathway genes with clinical outcomes in acute respiratory distress syndrome

Background

Altered plasma levels of protein C, thrombomodulin, and the endothelial protein C receptor are associated with poor clinical outcomes in patients with acute respiratory distress syndrome (ARDS). We hypothesized that common variants in these genes would be associated with mortality as well as ventilator-free and organ failure-free days in patients with ARDS.

Methods

We genotyped linkage disequilibrium-based tag single-nucleotide polymorphisms in the ProteinC, Thrombomodulin and Endothelial Protein C Reptor Genes among 320 self-identified white patients of European ancestry from the ARDS Network Fluid and Catheter Treatment Trial. We then tested their association with mortality as well as ventilator-free and organ-failure free days.

Results

The GG genotype of rs1042580 (p = 0.02) and CC genotype of rs3716123 (p = 0.002), both in the thrombomodulin gene, and GC/CC genotypes of rs9574 (p = 0.04) in the endothelial protein C receptor gene were independently associated with increased mortality. An additive effect on mortality (p < 0.001), ventilator-free days (p = 0.01), and organ failure-free days was observed with combinations of these high-risk genotypes. This association was independent of age, severity of illness, presence or absence of sepsis, and treatment allocation.

Conclusions

Genetic variants in thrombomodulin and endothelial protein C receptor genes are additively associated with mortality in ARDS. These findings suggest that genetic differences may be at least partially responsible for the observed associations between dysregulated coagulation and poor outcomes in ARDS.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1330-5) contains supplementary material, which is available to authorized users.

Understanding inherited genetic risk of adult glioma - a review

During the past six years, researchers have made major progress identifying common inherited genetic variation that increases risk for primary adult glioma. This paper summarizes knowledge about rare familial cancer syndromes that include adult glioma and reviews the available literature on the more recently discovered common inherited variation. Ten independent inherited variants in eight chromosomal regions have been convincingly associated with increased risk for adult glioma. Most of these variants increase relative risk of primary adult glioma by 20% to 40%, but the TP53 variant rs78378222 confers a two-fold relative risk (ie, 200%), and rs557505857 on chromosome 8 confers a six-fold relative risk of IDH-mutated astrocytomas and oligodendroglial tumors (ie, 600%). Even with a six-fold relative risk, the overall risk of developing adult glioma is too low for screening for the high-risk variant on chromosome 8. Future studies will help clarify which inherited adult glioma risk variants are associated with subtypes defined by histology and/or acquired tumor mutations. This review also provides an information sheet for primary adult glioma patients and their families.

Glioma Groups Based on 1p/19q, IDH, and TERT Promoter Mutations in Tumors

BACKGROUND

The prediction of clinical behavior, response to therapy, and outcome of infiltrative glioma is challenging. On the basis of previous studies of tumor biology, we defined five glioma molecular groups with the use of three alterations: mutations in the TERT promoter, mutations in IDH, and codeletion of chromosome arms 1p and 19q (1p/19q codeletion). We tested the hypothesis that within groups based on these features, tumors would have similar clinical variables, acquired somatic alterations, and germline variants.

METHODS

We scored tumors as negative or positive for each of these markers in 1087 gliomas and compared acquired alterations and patient characteristics among the five primary molecular groups. Using 11,590 controls, we assessed associations between these groups and known glioma germline variants.

RESULTS

Among 615 grade II or III gliomas, 29% had all three alterations (i.e., were triple-positive), 5% had TERT and IDH mutations, 45% had only IDH mutations, 7% were triple-negative, and 10% had only TERT mutations; 5% had other combinations. Among 472 grade IV gliomas, less than 1% were triple-positive, 2% had TERT and IDH mutations, 7% had only IDH mutations, 17% were triple-negative, and 74% had only TERT mutations. The mean age at diagnosis was lowest (37 years) among patients who had gliomas with only IDH mutations and was highest (59 years) among patients who had gliomas with only TERT mutations. The molecular groups were independently associated with overall survival among patients with grade II or III gliomas but not among patients with grade IV gliomas. The molecular groups were associated with specific germline variants.

CONCLUSIONS

Gliomas were classified into five principal groups on the basis of three tumor markers. The groups had different ages at onset, overall survival, and associations with germline variants, which implies that they are characterized by distinct mechanisms of pathogenesis. (Funded by the National Institutes of Health and others.).

Abstract 271: Rising rates of acute lymphocytic leukemia in Hispanic children: A review of trends in childhood leukemia incidence from 1973-2010

Background: Childhood leukemia is the most common cancer in children under 20 years of age in the United States, and incidence rates have increased over the last few decades. The incidence rate for all childhood leukemia is higher among Hispanic children [2006-2010 age-adjusted incidence rate (AAIR)= 5.71; 95%CI: 5.47, 5.97] than among non-Hispanic White children (2006-2010 AAIR=3.95; 95%CI: 3.81, 4.09). This analysis aims to describe secular trends from 1992-2010 in the incidence of childhood leukemia, independently for Hispanic and non-Hispanic children.

Methods: Surveillance, Epidemiology and End Results (SEER) data were used to evaluate trends in the incidence of childhood leukemia diagnosed in children less than 20 years of age between 1992-2010 by ethnicity. Trends among Hispanic and non-Hispanic children were examined overall and by age, gender, and histologic subtype. AAIRs, annual percent change (APC) estimates, and 95% confidence intervals (95%CIs) were calculated using SEER*stat v.8.0.4.

Results: Hispanic children were more likely than non-Hispanic children to be diagnosed with leukemia (all subtypes combined), and with acute lymphocytic leukemia when examined by gender and by age (0-4, 5-9, 10-14, 15-19 years at diagnosis). A greater increase in AAIRs was observed for Hispanic children as compared to non-Hispanic children for all types of leukemia from 1992-2010 (APCHispanic=1.16; 95%CI: 0.55, 1.76; APCnon-Hispanic=0.52; 95%CI: 0.01, 1.03). When restricting to acute lymphocytic leukemias (ALL), statistically significant increases were observed for Hispanic children (APC=1.31; 95%CI:0.68, 1.94), but not for non-Hispanic children (APC=0.50; 95%CI: -0.19, 1.19). Among Hispanic children, the strongest increase was found among children diagnosed from 10-19 years of age. Incidence rates were higher for Hispanic males (AAIR=5.26; 95%CI: 4.93, 5.60;) than for Hispanic females (AAIR=4.07; 95%CI: 3.78, 4.39).

Conclusion: Incidence rates of childhood leukemia rose from 1992-2010, with the greatest increase for ALL among older Hispanic children (aged 10-19 years). In future studies aimed at evaluating exposures responsible for increasing incidence rates of childhood ALL, researchers should consider risk factors that may explain the rising rates among Hispanic children.

Citation Format: Jessica Barrington-Trimis, Myles Cockburn, Catherine Metayer, W. James Gauderman, Joseph Wiemels, Roberta McKean-Cowdin. Rising rates of acute lymphocytic leukemia in Hispanic children: A review of trends in childhood leukemia incidence from 1973-2010. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 271. doi:10.1158/1538-7445.AM2014-271

Interaction of allergy history and antibodies to specific varicella-zoster virus proteins on glioma risk

Glioma is the most common cancer of the central nervous system but with few confirmed risk factors. It has been inversely associated with chicken pox, shingles and seroreactivity to varicella virus (VZV), as well as to allergies and allergy-associated IgE. The role of antibody reactivity against individual VZV antigens has not been assessed. Ten VZV-related proteins, selected for high immunogenicity or known function, were synthesized and used as targets for antibody measurements in the sera of 143 glioma cases and 131 healthy controls selected from the San Francisco Bay Area Adult Glioma Study. Glioma cases exhibited significantly reduced seroreactivity compared to controls for six antigens, including proteins IE63 [odds ratio (OR) = 0.26, 95% confidence interval (CI): 0.12-0.58, comparing lowest quartile to highest) and the VZV-unique protein ORF2p (OR = 0.44, 95% CI: 0.21-0.96, lowest quartile to highest). When stratifying the study population into those with low and high self-reported allergy history, VZV protein seroreactivity was only associated inversely with glioma among individuals self-reporting more than two allergies. The data provide insight into both allergy and VZV effects on glioma: strong anti-VZV reactions in highly allergic individuals are associated with reduced occurrence of glioma. This result suggests a role for specificity in the anti-VZV immunity in brain tumor suppression for both individual VZV antigens and in the fine-tuning of the immune response by allergy. Anti-VZV reactions may also be a biomarker of effective CNS immunosurveillance owing to the tropism of the virus.

Dental x-rays and risk of meningioma: response to Drs. Calnon, Jorgensen, and White

Report of past dental x-rays has been reported to be associated with the diagnosis of intracranial meningioma. The authors respond to commentary regarding their recent case/control study of the topic.

Serum autoantibodies to pancreatic cancer antigens as biomarkers of pancreatic cancer in a San Francisco Bay Area case-control study

BACKGROUND

Screening and early diagnosis tools are lacking for pancreatic adenocarcinoma; most patients are diagnosed with metastatic disease. Autoantibodies to tumor-associated antigens (TAAs) can be present months to years before diagnosis and hold promise as biomarkers for early detection.

METHODS

TAAs to pancreatic cancer autoantibodies CTDSP1 (carboxy-terminal domain, RNA polymerase II, polypeptide A, small phosphatase 1), MAPK9 (mitogen-activated protein kinase 9), and NR2E3 (nuclear receptor subfamily 2, group E, member 3), which were identified as potentially promising biomarkers in exploratory studies, were evaluated in serum from participants (300 cases, 300 controls) in a population-based case-control pancreatic cancer study in the San Francisco Bay Area. Patients were identified through cancer registry rapid case ascertainment, newly diagnosed from 1995 to 1999 and followed up through 2008. Autoantibody levels were analyzed as continuous and grouped (quartiles) variables. Multivariable unconditional logistic regression was used to compute odds ratios (ORs) as estimates of autoantibody levels associated with disease status. Kaplan-Meier product limit estimates and multivariable Cox proportional hazards regression were used to assess autoantibody levels associated with case survival duration.

RESULTS

Cases had higher levels of CTDSP1 (P = .004), MAPK9 (P = .0002), and NR2E3 (P ≤ .0001) autoantibodies than controls (fourth vs first quartile: CTDSP1 OR = 1.7, MAPK9 OR = 2.5, NR2E3 OR = 4.0). High body mass index and tobacco use were associated with levels in controls but were not statistical confounders. High CTDSP1 levels were somewhat associated with better survival (hazard ratio = 0.77, P = .07).

CONCLUSIONS

Combined with previous results, this study contributes evidence that cancer-related host immune-response factors may be useful diagnostic screening tools and prognostic indicators for pancreatic cancer. Further studies are needed to critically assess the value of autoantibody panels to TAAs in diagnostic screening, prognosis, and immunotherapy of pancreatic and other cancers.

Perspectives on the causes of childhood leukemia

Acute leukemia is the most common cancer in children but the causes of the disease in the majority of cases are not known. About 80% are precursor-B cell in origin (CD19+, CD10+), and this immunophenotype has increased in incidence over the past several decades in the Western world. Part of this increase may be due to the introduction of new chemical exposures into the child's environment including parental smoking, pesticides, traffic fumes, paint and household chemicals. However, much of the increase in leukemia rates is likely linked to altered patterns of infection during early childhood development, mirroring causal pathways responsible for a similarly increased incidence of other childhood-diagnosed immune-related illnesses including allergy, asthma, and type 1 diabetes. Factors linked to childhood leukemia that are likely surrogates for immune stimulation include exposure to childcare settings, parity status and birth order, vaccination history, and population mixing. In case-control studies, acute lymphoblastic leukemia (ALL) is consistently inversely associated with greater exposure to infections, via daycare and later birth order. New evidence suggests also that children who contract leukemia may harbor a congenital defect in immune responder status, as indicated by lower levels of the immunosuppressive cytokine IL-10 at birth in children who grow up to contract leukemia, as well as higher need for clinical care for infections within the first year of life despite having lower levels of exposure to infections. One manifestation of this phenomenon may be leukemia clusters which tend to appear as a leukemia "outbreak" among populations with low herd immunity to a new infection. Critical answers to the etiology of childhood leukemia will require incorporating new tools into traditional epidemiologic approaches - including the classification of leukemia at a molecular scale, better exposure assessments at all points in a child's life, a comprehensive understanding of genetic risk factors, and an appraisal of the interplay between infectious exposures and the status of immune response in individuals.