Genetic errors of immunity distinguish pediatric nonmalignant lymphoproliferative disorders.

BACKGROUND: Pediatric nonmalignant lymphoproliferative disorders (PLPDs) are clinically and genetically heterogeneous. Long-standing immune dysregulation and lymphoproliferation in children may be life-threatening, and a paucity of data exists to guide evaluation and treatment of children with PLPD. OBJECTIVE: The primary objective of this study was to ascertain the spectrum of genomic immunologic defects in PLPD. Secondary objectives included characterization of clinical outcomes and associations between genetic diagnoses and those outcomes. METHODS: PLPD was defined by persistent lymphadenopathy, lymph organ involvement, or lymphocytic infiltration for more than 3 months, with or without chronic or significant Epstein-Barr virus (EBV) infection. Fifty-one subjects from 47 different families with PLPD were analyzed using whole exome sequencing. RESULTS: Whole exome sequencing identified likely genetic errors of immunity in 51% to 62% of families (53% to 65% of affected children). Presence of a genetic etiology was associated with younger age and hemophagocytic lymphohistiocytosis. Ten-year survival for the cohort was 72.4%, and patients with viable genetic diagnoses had a higher survival rate (82%) compared to children without a genetic explanation (48%, P = .03). Survival outcomes for individuals with EBV-associated disease and no genetic explanation were particularly worse than outcomes for subjects with EBV-associated disease and a genetic explanation (17% vs 90%; P = .002). Ascertainment of a molecular diagnosis provided targetable treatment options for up to 18 individuals and led to active management changes for 12 patients. CONCLUSIONS: PLPD defines children at high risk for mortality, and whole exome sequencing informs clinical risks and therapeutic opportunities for this diagnosis.

Programmed cell death ligand 1 expression in aggressive pediatric non-Hodgkin lymphomas: frequency, genetic mechanisms, and clinical significance.

Programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) are immunomodulatory molecules overexpressed in lymphomas and are promising immunotherapy targets for hematologic malignancies. However, studies of PD-1/PD-L1 overexpression and their clinical significance in aggressive pediatric non-Hodgkin lymphomas (NHL) are limited. We assessed PD-1/PD-L1 overexpression using immunohistochemistry in 68 aggressive pediatric NHL: ALK-positive anaplastic large cell lymphoma (ALK+ ALCL, n=8), Burkitt lymphoma (BL, n=27), and large B-cell lymphoma (LBCL) de novo LBCL, n=22 and diffuse LBCL arising as monomorphic post-transplant lymphoproliferative disorder [PTLD-DLBCL], n=11. In LBCL, correlations between PD-L1 overexpression and Epstein-Barr virus (EBV) status, cell of origin, stage, nodal status, overall survival (OS), and event-free survival (EFS) were examined. The genetic mechanisms of PD-L1 overexpression were investigated using targeted next-generation sequencing (NGS) and cytogenetic data. All ALK+ ALCL samples, 50.0% of de novo LBCL (11/22), 72.7% of PTLD-DLBCL (8/11), and no BL overexpressed PD-L1. Overexpressed PD-L1 correlated with EBV positivity (P=0.033) in LBCL and lower EFS in de novo LBCL (P=0.017). NGS of select LBCL revealed distinct somatic mutations and an ultra-hypermutated PTLD-DLBCL. Most cases with 9p24.1 copy gains overexpressed PD-L1 although some cases had no discernible genetic drivers of PD-L1 overexpression. Overexpressed PD-L1 is common in pediatric LBCL, associated with EBV positivity and 9p24.1 gains, and may have prognostic significance in de novo LBCL. Furthermore, diverse molecular mechanisms for PD-L1 overexpression in aggressive pediatric NHL can occur. Thus, additional studies exploring the therapeutic and prognostic significance and molecular mechanisms of PD-L1 overexpression in aggressive pediatric NHL are warranted.

Genetic variation in the body mass index of adult survivors of childhood acute lymphoblastic leukemia: A report from the Childhood Cancer Survivor Study and the St. Jude Lifetime Cohort.

BACKGROUND: Treatment characteristics such as cranial radiation therapy (CRT) do not fully explain adiposity risk in childhood acute lymphoblastic leukemia (ALL) survivors. This study was aimed at characterizing genetic variation related to adult body mass index (BMI) among survivors of childhood ALL. METHODS: Genetic associations of BMI among 1458 adult survivors of childhood ALL (median time from diagnosis, 20 years) were analyzed by multiple approaches. A 2-stage genome-wide association study in the Childhood Cancer Survivor Study (CCSS) and the St. Jude Lifetime Cohort Study (SJLIFE) was performed. BMI was a highly polygenic trait in the general population. Within the known loci, the BMI percent variance explained was estimated, and additive interactions (chi-square test) with CRT in the CCSS were evaluated. The role of DNA methylation in CRT interaction was further evaluated in a subsample of ALL survivors. RESULTS: In a meta-analysis of the CCSS and SJLIFE, 2 novel loci associated with adult BMI among survivors of childhood ALL (LINC00856 rs575792008 and EMR1 rs62123082; PMeta < 5E-8) were identified. It was estimated that the more than 700 known loci explained 6.2% of the variation in adult BMI in childhood ALL survivors. Within the known loci, significant main effects for 23 loci and statistical interactions with CRT at 9 loci (P < 7.0E-5) were further identified. At 2 CRT-interacting loci, DNA methylation patterns may have differed by age. CONCLUSIONS: Adult survivors of childhood ALL have genetic heritability for BMI similar to that observed in the general population. This study provides evidence that treatment with CRT can modify the effect of genetic variants on adult BMI in childhood ALL survivors.

Novel risk factors for glucarpidase use in pediatric acute lymphoblastic leukemia: Hispanic ethnicity, age, and the ABCC4 gene.

BACKGROUND: Carboxypeptidase G2 (CPDG2 ; glucarpidase) is a rescue drug for patients at risk for kidney injury from high-dose methotrexate (MTX). As there are no strategies for predicting patients who will require CDPG2 , we evaluated the role of demographic, clinical, and genetic factors for CPDG2 use. PROCEDURE: Cases who received CPDG2 and controls who did not were identified by chart review of acute lymphoblastic leukemia (ALL) patients who received MTX doses between 1000 and 5000 mg/m2 between 2010 and 2017. We used multivariable Bayesian logistic regression to evaluate the association of CPDG2 use with demographic and clinical variables and, on a subset of patients, with genetic ancestry and 49 single nucleotide variants previously associated with MTX toxicity. RESULTS: We identified 423 patients who received 1592 doses of MTX. Of the 18 patients who received CPDG2 , 17 (94%) were Hispanic. No patients who received 1000 or 2000 mg/m2 of MTX received CPDG2 . Hispanic ethnicity (odds ratio: 4.68; 95% compatibility interval: 1.63-15.06) and older age (1.87 [1.17-3.17]) were associated with receiving CPDG2 . Of the 177 patients in the genomic cohort, 11 received CPDG2 . Each additional G allele of rs7317112 in ABCC4 increased the odds of requiring CPDG2 (3.10 [1.12-6.75]). Six other loci (NTRK1/rs10908521, TSG1/rs9345389, STT3B/rs1353327, SCLO1B1/rs4149056, GATA3/rs3824662, ARID5B/rs10821936) demonstrated probabilities of association between 88% and 97%. CONCLUSION: We demonstrated that demographic characteristics, including Hispanic ethnicity and age, are associated with CPDG2 use. Additionally, we provide evidence that inherited genetic variation is associated with risk of requiring CPDG2 . If validated in independent populations, this information could be leveraged to develop targeted toxicity prevention strategies for children with ALL.

An evidence-based, risk-adapted algorithm for antifungal prophylaxis reduces risk for invasive mold infections in children with hematologic malignancies.

BACKGROUND: Children with hematologic malignancies, especially those who receive intensive chemotherapy, are at high risk for invasive mold infections (IMI) that confer substantial mortality. Randomized controlled trials support the use of antifungal prophylaxis with antimold activity as an optimal strategy for risk reduction in this population, but studies outlining the practical application of evidence-based recommendations are lacking. PROCEDURE: We conducted a 15-year, single-institution retrospective review in a diverse cohort of children with hematologic malignancies treated with chemotherapy to determine the incidence of proven or probable IMI diagnosed between 2006 and 2020. Multivariable logistic regression was used to identify host and disease factors associated with IMI risk. We then compared the incidence and type of IMI and related factors before and after 2016 implementation of an evidence-based, risk-adapted antifungal prophylaxis algorithm that broadened coverage to include molds in patients at highest risk for IMI. RESULTS: We identified 61 cases of proven or probable IMI in 1456 patients diagnosed with hematologic malignancies during the study period (4.2%). Implementation of an antifungal prophylaxis algorithm reduced the IMI incidence in this population from 4.8% to 2.9%. Both Hispanic ethnicity and cancer diagnosis prior to 2016 were associated with risk for IMI. CONCLUSION: An evidence-based, risk-adapted approach to antifungal prophylaxis for children with hematologic malignancies is an effective strategy to reduce incidence of IMI.

COVID-19 outcomes in a large pediatric hematology-oncology center in Houston, Texas.

An understanding of the behavior of SARS-CoV-2 in pediatric hematology-oncology patients is essential to the optimal management of these patients during the COVID-19 pandemic. This study describes the characteristics and outcomes of COVID-19 disease in children with cancer or hematologic disorders treated at a large children's hospital. A retrospective cohort study was conducted at Texas Children's Cancer and Hematology Center from January 1, 2020 to September 30, 2020. All patients with a primary hematology-oncology diagnosis and SARS-CoV-2 positivity by reverse transcription polymerase chain reaction were identified. Clinical and laboratory data were obtained from the medical record. Descriptive analyses were performed to evaluate COVID-19-related outcomes and risk factors for severe disease in this population. We identified 109 patients with COVID-19 disease, including 52 hematology, 51 oncology, and 6 HSCT patients; median age was 10.3 years (IQR 4.4-15.9), and 58.7% were male. Seventy-four percent of the patients were managed in the outpatient setting. Patients with sickle cell disease were more likely to require hospitalization. ICU care was needed in 8% (n = 9) of the entire cohort, and mechanical ventilation was required in 6.4% (6 oncology patients, 1 hematology patient). COVID-19 contributed to the deaths of two cancer patients. No deaths occurred in hematology or HSCT patients. In conclusion, the risk of severe COVID-19 complications is slightly higher in pediatric hematology-oncology patients than in the general pediatric population but lower than initially feared. For most asymptomatic patients, primary disease management may continue as planned, but treatment decisions must be individualized.

DNA methylation and obesity in survivors of pediatric acute lymphoblastic leukemia: A report from the Childhood Cancer Survivor Study.

Because survivors of pediatric acute lymphoblastic leukemia (ALL) are more likely to be obese than unaffected contemporaries, we compared DNA methylation profiles between normal-weight and obese survivors at adiposity-associated CpG sites previously-reported by epigenome-wide association studies (EWAS) of body mass index (BMI) in the general population. We selected 96 ALL survivors from the Childhood Cancer Survivor Study: 48 obese and 48 normal weight. The Illumina HumanMethylation450 BeadChip was used to compare DNA methylation at 211 loci identified in EWAS of BMI in the general population. Thirty-nine loci were associated (false discovery rate <0.05) with obesity among survivors who only received chemotherapy (n = 49). No loci were significantly associated with obesity among CRT-exposed survivors (n = 47). Our results suggest that previously identified BMI-DNA methylation loci are associated with obesity in ALL survivors who were spared CRT, while no loci were significantly associated with obesity in survivors who received CRT.

Predictors of Suboptimal Follow-up in Pediatric Cancer Survivors.

Attendance to follow-up care after completion of cancer treatment is an understudied area. We examined demographic, clinical, and socioeconomic predictors of follow-up by pediatric cancer patients at a large center in 442 newly diagnosed patients using multivariable logistic regression analyses. Patients who did not return to clinic for at least 1000 days were considered lost to follow-up. Two hundred forty-two (54.8%) patients were lost. In multivariable analyses, the following variables were independent predictors of being lost to follow-up: treatment with surgery alone (odds ratio [OR]=6.7; 95% confidence interval [CI], 3.1-14.9), older age at diagnosis (reference, 0 to 4; ages, 5 to 9: OR=1.8, 95% CI, 1.1-3; ages, 10 to 14: OR=3.3; CI, 1.8-6.1; and ages, 15 and above: OR=4.8; CI, 2.1-11.7), lack of history of stem cell transplantation (OR=2, 95% CI, 1.04-3.7) and lack of insurance (OR=3.4; CI, 1.2-9.2). Hispanic patients had the best follow-up rates (53.7%) compared to whites and blacks (P=0.03). Attendance to long-term follow-up care is suboptimal in childhood cancer survivors. Predictors that were associated with nonattendance can be used to design targeted interventions to improve follow-up care for survivors of pediatric cancer.

Prevalence and Predictors of Overweight and Obesity Among a Multiethnic Population of Pediatric Acute Lymphoblastic Leukemia Survivors: A Cross-Sectional Assessment.

As previous studies of obesity in survivors of pediatric acute lymphoblastic leukemia (ALL) have primarily been conducted among non-Hispanic white survivors or children treated on older protocols, our objective was to describe the prevalence and correlates of overweight status among an ethnically diverse population of pediatric ALL survivors, largely treated with more contemporary therapies. We evaluated the overweight/obesity status of pediatric ALL survivors (n=406) followed in the Texas Children's Cancer Center between 2004 and 2014. Survivors were classified as underweight, normal weight, overweight, or obese on the basis of their body mass index at their most current follow-up visit. Our results showed that Hispanic ethnicity (39% of the subjects) was associated with being overweight (adjusted odds ratio=1.88; 95% confidence interval, 1.13-3.14) or obese (adjusted odds ratio=2.84; 95% confidence interval, 1.59-5.06) at follow-up, even after adjusting for cranial radiotherapy (CRT) exposure. Body mass index z-score at diagnosis was also associated with overweight/obesity at follow-up. In addition, there was a statistically significant interaction between younger age at diagnosis and CRT, indicating that younger age at diagnosis was associated with obesity among patients who received CRT. These findings may help identify pediatric ALL patients that are at increased risk of being overweight or obese after treatment.

Birth Characteristics and Childhood Leukemia Risk: Correlations With Genetic Markers.

Birth characteristics such as birth order, birth weight, birth defects, and Down syndrome showed some of the first risk associations with childhood leukemia. Examinations of correlations between birth characteristics and leukemia risk markers have been limited to birth weight-related genetic polymorphisms. We integrated information on nongenetic and genetic markers by evaluating the relationship of birth characteristics, genetic markers for childhood acute lymphoblastic leukemia (ALL) susceptibility, and ALL risk together. The multiethnic study consisted of cases with childhood ALL (n=161) and healthy controls (n=261). Birth characteristic data were collected through questionnaires, and genotyping was achieved by TaqMan SNP Genotyping Assays. We observed risk associations for birth weight over 4000 g (odds ratios [OR]=1.93; 95% confidence interval [CI], 1.16-3.19), birth length (OR=1.18 per inch; 95% CI, 1.01-1.38), and with gestational age (OR=1.10 per week; 95% CI, 1.00-1.21). Only the HFE tag single-nucleotide polymorphism (SNP) rs9366637 showed an inverse correlation with a birth characteristic, gestational age, with a gene-dosage effect (P=0.005), and in interaction with a transferrin receptor rs3817672 genotype (Pinteraction=0.05). This correlation translated into a strong association for rs9366637 with preterm birth (OR=5.0; 95% CI, 1.19-20.9). Our study provides evidence for the involvement of prenatal events in the development of childhood ALL. The inverse correlation of rs9366637 with gestational age has implications on the design of HFE association studies in birth weight and childhood conditions using full-term newborns as controls.

Algorithm for analysis of administrative pediatric cancer hospitalization data according to indication for admission.

BACKGROUND: Childhood cancer relies heavily on inpatient hospital services to deliver tumor-directed therapy and manage toxicities. Hospitalizations have increased over the past decade, though not uniformly across childhood cancer diagnoses. Analysis of the reasons for admission of children with cancer could enhance comparison of resource use between cancers, and allow clinical practice data to be interpreted more readily. Such comparisons using nationwide data sources are difficult because of numerous subdivisions in the International Classification of Diseases Clinical Modification (ICD-9) system and inherent complexities of treatments. This study aimed to develop a systematic approach to classifying cancer-related admissions in administrative data into categories that reflected clinical practice and predicted resource use. METHODS: We developed a multistep algorithm to stratify indications for childhood cancer admissions in the Kids Inpatient Databases from 2003, 2006 and 2009 into clinically meaningful categories. This algorithm assumed that primary discharge diagnoses of cancer or cytopenia were insufficient, and relied on procedure codes and secondary diagnoses in these scenarios. Clinical Classification Software developed by the Healthcare Cost and Utilization Project was first used to sort thousands of ICD-9 codes into 5 mutually exclusive diagnosis categories and 3 mutually exclusive procedure categories, and validation was performed by comparison with the ICD-9 codes in the final admission indication. Mean cost, length of stay, and costs per day were compared between categories of indication for admission. RESULTS: A cohort of 202,995 cancer-related admissions was grouped into four categories of indication for admission: chemotherapy (N=77,791, 38%), to undergo a procedure (N=30,858, 15%), treatment for infection (N=30,380, 15%), or treatment for other toxicities (N=43,408, 21.4%). The positive predictive value for the algorithm was >95% for each category. Admissions for procedures had higher mean hospital costs, longer hospital stays, and higher costs per day compared with other admission reasons (p<0.001). CONCLUSIONS: This is the first description of a method for grouping indications for childhood cancer admission within an administrative dataset into clinically relevant categories. This algorithm provides a framework for more detailed analyses of pediatric hospitalization data by cancer type.

Gene-environment interactions and the risk of childhood acute lymphoblastic leukemia: exploring the role of maternal folate genes and folic Acid fortification.

Few studies have evaluated the interaction of folic acid fortification and folate metabolic genes on the risk of childhood acute lymphoblastic leukemia (ALL). Because folate status is influenced by both intake and genetic variation, the objective of this study was to explore maternal folate metabolic gene-folic acid fortification interactions and the risk of childhood ALL. The study population consisted of 120 ALL case-parent triads recruited from Texas Children's Cancer Center between 2003 and 2010. For this analysis, we focused on 13 maternal single nucleotide polymorphisms (SNPs) in 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR). Prefortification was defined as delivery before January 1997 and postfortification as delivery in or after January 1997. We used a two-step approach to evaluate gene-environment interactions. First, a case-only approach was used, as this design provides greater power in the assessment of gene-environment interactions compared to other approaches. Second, we confirmed all statistically significant interactions using a log-linear approach among case-parent triads. Only one of 13 interactions evaluated was confirmed in step 2. Specifically, mothers with the minor allele of MTR rs1804742 and who delivered during the prefortification period were at a greater risk of having a child with ALL (OR = 1.54, 95% CI: 0.82-2.88), compared to those mothers who delivered during the postfortification period (OR = 0.81, 95% CI: 0.22-2.99, P for interaction = .03). In one of the few studies to evaluate maternal folate metabolic genotype-folic acid interactions, we found limited evidence that the maternal MTR rs1804742 appeared to interact with higher folic acid levels to influence childhood ALL risk.

Novel and replicated clinical and genetic risk factors for toxicity from high-dose methotrexate in pediatric acute lymphoblastic leukemia.

STUDY OBJECTIVE: Methotrexate (MTX) is a key component of treatment for high-risk pediatric acute lymphoblastic leukemia (ALL) but may cause acute kidney injury and prolonged hospitalization due to delayed clearance. The purpose of this study is to identify clinical and genetic factors that may predict which children are at risk for creatinine increase and prolonged MTX clearance. DESIGN: We conducted a single-center, retrospective cohort study of pediatric patients with ALL who received 4000-5000 mg/m2 of MTX. Measurements We performed germline genotyping to determine genetic ancestry and allele status for 49 single nucleotide polymorphisms (SNPs) identified from the literature as related to MTX disposition. Bayesian hierarchical ordinal regression models for creatinine increase and for prolonged MTX clearance were developed. MAIN RESULTS: Hispanic ethnicity, body mass index (BMI) < 3%, BMI between 85%-95%, and Native American genetic ancestry were found to be associated with an increased risk for creatinine elevation. Older age, Black race, and use of the intensive monitoring protocol were associated with a decreased risk for creatinine elevation. Older age, B- compared to T-ALL, and the minor alleles of rs2838958/SLC19A1 and rs7317112/ABCC4 were associated with an increased risk for delayed clearance. Black race, MTX dose reduction, and the minor allele of rs2306283/SLCO1B1 were found to be associated with a decreased risk for delayed clearance. CONCLUSIONS: These predictors of MTX toxicities may allow for more precise individualized toxicity risk prediction.

A case-parent triad assessment of folate metabolic genes and the risk of childhood acute lymphoblastic leukemia.

PURPOSE: We conducted a case-parent triad study evaluating the role of maternal and offspring genotypes in the folate metabolic pathway on childhood acute lymphoblastic leukemia (ALL) risk. METHODS: Childhood ALL case-parent triads (n = 120) were recruited from Texas Children's Hospital. DNA samples were genotyped using the Sequenom iPLEX MassARRAY for 68 tagSNPs in six folate metabolic pathway genes (MTHFR, MTRR, MTR, DHFR, BHMT, and TYMS). Log-linear modeling was used to examine the associations between maternal and offspring genotypes and ALL. RESULTS: After controlling for the false discovery rate (<0.1), there were 20 significant maternal effects in the following genes: BHMT (n = 3), MTR (n = 12), and TYMS (n = 5). For instance, maternal genotypes for BHMT rs558133 (relative risk [RR] = 0.51, 95 % confidence interval [CI]: 0.30-0.87, p = 0.008, Q = 0.08) and MTR rs2282369 (RR = 0.46, 95 % CI: 0.27-0.80, p = 0.004, Q = 0.08) were associated with ALL. There were no significant offspring effects after controlling for the false discovery rate. CONCLUSIONS: This is one of the few studies conducted to evaluate maternal genetic effects in the context of childhood ALL risk. Furthermore, we employed a family-based design that is less susceptible to population stratification bias in the estimation of maternal genetic effects. Our findings suggest that maternal genetic variation in the folate metabolic pathway is relevant in the etiology of childhood ALL. The observed maternal genetic effects support the need for continued research of how the uterine environment may influence risk of ALL.

A meta-analysis of MTHFR C677T and A1298C polymorphisms and risk of acute lymphoblastic leukemia in children.

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms have been implicated in childhood acute lymphoblastic leukemia (ALL) risk, but previously published studies were inconsistent and recent meta-analyses were not adequate. PROCEDURES: In a meta-analysis of 21 publications with 4,706 cases and 7,414 controls, we used more stringent inclusion method and summarized data on associations between MTHFR C677T and A1298C polymorphisms and childhood ALL risk. RESULTS: We found an overall association between 677T variant genotypes and reduced childhood ALL risk. Specifically, in the dominant genetic model, an association was found in a fixed-effect (TT + CT vs. CC: OR = 0.92; 95% CI = 0.85-0.99) but not random-effect model, whereas such an association was observed in both homozygote genetic model (TT vs. CC: OR = 0.80; 95% CI = 0.70-0.93 by fixed effects and OR = 0.78; 95% CI = 0.65-0.93 by random effects) and recessive genetic model (TT vs. CC + CT: OR = 0.83; 95% CI = 0.72-0.95 by fixed effects and OR = 0.84; 95% CI = 0.73-0.97 by random effects). These associations were also observed in subgroups by ethnicity: for Asians in all models except for the dominant genetic model by random effect and for Caucasians in all models except for the recessive genetic model. However, the A1298C polymorphism did not appear to have an effect on childhood ALL risk. CONCLUSIONS: These results suggest that the MTHFR C677T, but not A1298C, polymorphism is a potential biomarker for childhood ALL risk.

Germline Genetic and Treatment-Related Risk Factors for Diabetes Mellitus in Survivors of Childhood Cancer: A Report From the Childhood Cancer Survivor Study and St Jude Lifetime Cohorts.

PURPOSE: To characterize germline genetic risk factors of diabetes mellitus among long-term survivors of childhood cancer. METHODS: Adult survivors of childhood cancer from the Childhood Cancer Survivor Study (CCSS) Original Cohort (n = 5,083; 383 with diabetes) were used to conduct a discovery genome-wide association study. Replication was performed using the CCSS Expansion (n = 2,588; 40 with diabetes) and the St Jude Lifetime (SJLIFE; n = 3,351; 208 with diabetes) cohorts. Risk prediction models, stratified on exposure to abdominal radiation, were calculated using logistic regression including attained age, sex and body mass index, diagnosis, alkylating chemotherapy, age at cancer diagnosis, and a polygenic risk score (PRS) on the basis of 395 diabetes variants from the general population. Area under the receiver operating characteristic curve (AUC) was calculated for models on the basis of traditional risk factors, clinical risk factors, and PRS. RESULTS: There was a genome-wide significant association of rs55849673-A with diabetes among survivors (odds ratio, 2.9; 95% CI, 2.0 to 4.2; P = 3.7 × 10-8), which is related to expression of ERCC6L2 in the Genotype-Tissue Expression project. The association of rs55849673-A was observed largely among survivors not exposed to abdominal radiation (odds ratio = 3.5, P = 1.1 × 10-7) and the frequency of rs55849673-A was consistently higher among diabetic survivors in the CCSS Expansion and SJLIFE cohorts. Risk prediction models including traditional diabetes risk factors, clinical risk factors and PRS had an optimism-corrected AUC of 0.801, with an AUC of 0.751 in survivors treated with abdominal radiation versus 0.813 in survivors who did not receive abdominal radiation. CONCLUSION: There is evidence for a novel locus of diabetes among survivors not exposed to abdominal radiation. Further refinement and validation of clinic-based risk prediction models for diabetes among long-term survivors of childhood cancer is warranted.

Folate pathway polymorphisms predict deficits in attention and processing speed after childhood leukemia therapy.

BACKGROUND: Neurocognitive impairment occurs in 20-40% of childhood acute lymphoblastic leukemia (ALL) survivors, possibly mediated by folate depletion and homocysteine elevation following methotrexate treatment. We evaluated the relationship between folate pathway polymorphisms and neurocognitive impairment after childhood ALL chemotherapy. PROCEDURE: Seventy-two childhood ALL survivors treated with chemotherapy alone underwent a neurocognitive battery consisting of: Trail Making Tests A (TMTA) and B (TMTB), Grooved Pegboard Test Dominant-Hand and Nondominant-Hand, Digit Span subtest, and Verbal Fluency Test. We performed genotyping for: 10-methylenetetrahydrofolate reductase (MTHFR 677C>T and MTHFR 1298A>C), serine hydroxymethyltransferase (SHMT 1420C>T), methionine synthase (MS 2756 A>G), methionine synthase reductase (MTRR 66A>G), and thymidylate synthase (TSER). Student's two sample t-test and analysis of covariance were used to compare test scores by genotype. RESULTS: General impairment on the neurocognitive battery was related to MTHFR 1298A>C (P = 0.03) and MS 2756A>G (P = 0.05). Specifically, survivors with MTHFR 1298AC/CC genotypes scored, on average, 13 points lower on TMTB than those with MTHFR 1298AA genotype (P = 0.001). The MS 2756AA genotype was associated with a 12.2 point lower mean TMTA score, compared to MS 2756 AG/GG genotypes (P = 0.01). The TSER 2R/3R and 3R/3R genotypes were associated with an 11.4 point lower mean score on TMTB, compared to the TSER 2R/2R genotype (P = 0.03). Survivors with ≥6 folate pathway risk alleles demonstrated a 9.5 point lower mean TMTA score (P = 0.06) and 14.5 point lower TMTB score (P = 0.002) than survivors with <6 risk alleles. CONCLUSIONS: Folate pathway polymorphisms are associated with deficits in attention and processing speed after childhood ALL therapy.

Posttransplant lymphoproliferative disease following liver transplantation.

PURPOSE OF REVIEW: Despite contemporary immunosuppressive regimens, posttransplant lymphoproliferative disease (PTLD) remains a major complication after liver transplantation. This review highlights advances in the understanding of the pathophysiology, diagnosis, and management of PTLD in liver transplant recipients. RECENT FINDINGS: The spectrum of PTLD after liver transplant ranges from polymorphic lymphoproliferation to high-grade monoclonal lymphoma and is usually related to outgrowth of lymphocytes infected with Epstein-Barr virus (EBV). Risk factors for PTLD include EBV-seronegativity of the recipient, young age, intensity of immunosuppression, and the first year posttransplant. Measurement of EBV load by quantitative polymerase chain reaction assays is an important aid in the surveillance and diagnosis of PTLD although the specificity for PTLD is only about 50% (specificity for EBV is ∼100%). In patients diagnosed with PTLD, management options include reduction of immunosuppression, rituximab, combination chemotherapy, and adoptive immunotherapy. Outcomes have improved because rituximab has been incorporated into treatment regimens, and immunotherapy approaches show promise. SUMMARY: PTLD is a significant complication after liver transplantation, particularly in children. Advances in early detection approaches have aided in the diagnosis and management of PTLD, but further research to identify better predictive biomarkers is needed to improve risk-based treatment strategies.