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1.  Identification of TP53 as an Acute Lymphocytic Leukemia Susceptibility Gene Through Exome Sequencing 
Pediatric blood & cancer  2012;60(6):E1-E3.
Although acute lymphocytic leukemia (ALL) is the most common childhood cancer, genetic predisposition to ALL remains poorly understood. Whole-exome sequencing was performed in an extended kindred in which five individuals had been diagnosed with leukemia. Analysis revealed a nonsense variant of TP53 which has been previously reported in families with sarcomas and other typical Li Fraumeni syndrome-associated cancers but never in a familial leukemia kindred. This unexpected finding enabled identification of an appropriate sibling bone marrow donor and illustrates that exome sequencing will reveal atypical clinical presentations of even well-studied genes.
PMCID: PMC3926299  PMID: 23255406
exome sequencing; acute lymphocytic leukemia; genetic predisposition to disease; genetic testing
2.  Constitutional Tandem Duplication of 9q34 that Truncates EHMT1 in a Child with Ganglioglioma 
Pediatric blood & cancer  2011;58(5):801-805.
Point mutations of EHMT1 or deletions and duplications of chromosome 9q34.3 are found in patients with variable neurologic and developmental disorders. Here, we present a child with congenital cataract, developmental and speech delay who developed a metastatic ganglioglioma with progression to anaplastic astrocytoma. Molecular analysis identified a novel constitutional tandem duplication in 9q34.3 with breakpoints in intron 1 of TRAF2 and intron 16 of EHMT1 generating a fusion transcript predicted to encode a truncated form of EHMT1. The ganglioglioma showed complex chromosomal aberrations with further duplication of the dup9q34. Thus, this unique tandem 9q34.3 duplication may impact brain tumor formation.
PMCID: PMC3202030  PMID: 21681934
9q34; ganglioglioma; EHMT1; histone methyltransferase
3.  Overexpression of ZNF342 by Juxtaposition with MPO Promoter/Enhancer in the Novel Translocation t(17;19)(q23;q13.32) in Pediatric Acute Myeloid Leukemia and Analysis of ZNF342 Expression in Leukemia 
Genes, chromosomes & cancer  2009;48(6):480-489.
We report a novel translocation t(17;19)(q22;q13.32) found in 100% of blast cells from a pediatric acute myeloid leukemia (AML) patient. Fluorescence in situ hybridization and vectorette polymerase chain reaction were used to precisely map the chromosomal breakpoint located on the derivative chromosome 17 at 352 bp 5′ of MPO, encoding myeloperoxidase a highly expressed protein in myeloid cells, and 2,085 bp 5′ of ZNF342 on 19q, encoding a transcription factor expressed in human stem cells and previously implicated in mouse models of leukemia. Analysis of RNA levels from the patient sample revealed significant overexpression of ZNF342, potentially contributing to AML formation. This is the first report of a translocation in myeloid leukemia occurring only in the promoter/enhancer regions of the two genes involved, similar to translocations commonly found in lymphoid malignancies. Analysis of ZNF342 protein levels in a large dataset of leukemia samples by reverse phase protein array showed that higher levels of ZNF342 expression in acute lymphoblastic leukemia was associated with poorer outcome (P = 0.033). In the myeloid leukemia samples with the highest ZNF342 expression, there was overrepresentation of FLT3 internal tandem duplication (P = 0.0016) and AML subtype M7 (P = 0.0002). Thus, overexpression of ZNF342 by translocation or other mechanisms contributes to leukemia biology in multiple hematopoietic compartments.
PMCID: PMC3385932  PMID: 19255975
5.  Identification of Genetic Susceptibility to Childhood Cancer through Analysis of Genes in Parallel 
Cancer genetics  2011;204(1):19-25.
Clinical cancer genetic susceptibility analysis typically proceeds sequentially beginning with the most likely causative gene. The process is time consuming and the yield is low particularly for families with unusual patterns of cancer. We determined the results of in parallel mutation analysis of a large cancer-associated gene panel. We performed deletion analysis and sequenced the coding regions of 45 genes (8 oncogenes and 37 tumor suppressor or DNA repair genes) in 48 childhood cancer patients who also (1) were diagnosed with a second malignancy under age 30, (2) have a sibling diagnosed with cancer under age 30 and/or (3) have a major congenital anomaly or developmental delay. Deleterious mutations were identified in 6 of 48 (13%) families, 4 of which met the sibling criteria. Mutations were identified in genes previously implicated in both dominant and recessive childhood syndromes including SMARCB1, PMS2, and TP53. No pathogenic deletions were identified. This approach has provided efficient identification of childhood cancer susceptibility mutations and will have greater utility as additional cancer susceptibility genes are identified. Integrating parallel analysis of large gene panels into clinical testing will speed results and increase diagnostic yield. The failure to detect mutations in 87% of families highlights that a number of childhood cancer susceptibility genes remain to be discovered.
PMCID: PMC3075924  PMID: 21356188
Cancer susceptibility; tumor suppressor genes; oncogenes; mutation analysis; rhabdoid tumors
Neuro-Oncology  2014;16(Suppl 3):iii24.
BACKGROUND: Additional insight into the molecular alterations driving pediatric central nervous system (CNS) tumors is urgently needed, given the significant morbidity and mortality associated with these cancers and the relative paucity of effective chemotherapeutic options. Advances in sequencing technologies now allow for provision of genome-scale data to oncologists caring for pediatric cancer patients but current experience with the clinical application of genomic sequencing is limited. The goal of the BASIC3 (Baylor Advancing Sequencing into Childhood Cancer Care) study is to determine the clinical impact of incorporating CLIA-certified tumor and constitutional whole exome sequencing (WES) into the care of children with newly diagnosed solid tumors. METHODS: The study follows pediatric patients with newly diagnosed CNS and non-CNS solid tumors (target enrollment n = 280) at Texas Children's Cancer Center for two years after performing CLIA-certified whole exome sequencing (WES) of blood and frozen tumor samples. Results are deposited into the electronic medical record and disclosed to families by their oncologist and a genetic counselor. The potential impact of tumor exome findings on clinical decision-making is assessed through review of the medical record and through surveys of the oncologists regarding prioritization of treatment options in the hypothetical event of tumor recurrence. RESULTS: To date, 133 subjects have been enrolled, including 47 patients with CNS tumors (35%) comprising a diverse representation of diagnoses. Despite limited diagnostic biopsies in many patients, tumor samples adequate for WES were obtained from 33/47 (70%) patients. Tumor WES results have been reported for the first 22 CNS tumors, revealing a median of 7 (range of 0 to 25) protein-altering mutations per tumor, including alterations of known cancer genes such as ARID1A, SMARCA4, BRAF, CTNNB1, DDX3X, NF2, FANCA, and NOTCH3. Notably, 12/22 (55%) tumors were found to harbour mutations only in genes not known to be recurrently altered in human cancers. CONCLUSIONS: These results demonstrate the feasibility of routine tumor WES in the pediatric neuro- oncology clinic. Potentially clinically-relevant mutations can be identified in a substantial proportion of patients but early results suggest that integration of parallel genomic technologies (e.g. RNAseq) to identify genetic alterations not detectable by WES will be necessary; such studies are ongoing. Orthotopic xenograft models and cell lines are being established to allow in vitro and in vivo analysis of tumors containing alterations of interest. Data further assessing the clinical utility of the tumor exomes are under study. Supported by NHGRI/NCI 1U01HG006485. SECONDARY CATEGORY: Neuropathology & Tumor Biomarkers.
PMCID: PMC4144597
7.  Genetic Testing and Cancer Risk Management Recommendations by Physicians for At-Risk Relatives 
Sequence-based cancer susceptibility testing results are described as negative, deleterious mutation or variant of uncertain significance (VUS). We studied the impact of different types of test results on clinical decision making.
Practicing physicians from five specialties in Texas completed an online case-based survey (n=225). Respondents were asked to make genetic testing and management recommendations for healthy at-risk relatives of cancer patients.
When the patient carried a deleterious BRCA1 mutation or VUS, 98% and 82% of physicians, respectively, recommended testing of at-risk relatives (p<0.0001). In both situations comprehensive BRCA1/2 analysis was selected most with a corresponding 9-fold increase in unnecessary genetic testing costs. There was no difference between physicians with (n=81) or without (n=134) prior BRCA1/2 testing experience (p=0.3869). Cancer risk management recommendations were most intense for the relative with a deleterious mutation compared with VUS, negative or no testing with 63%, 13%, 5% and 2%, respectively recommending oophorectomy (p<0.0001).
Independent of experience, or specialty, physicians chose more comprehensive testing for healthy relatives than current guidelines recommend. In contrast management decisions demonstrated the uncertainty associated with a VUS. Utilization of genetic professionals and education of physicians on family-centered genetic testing may improve efficacy and substantially reduce costs.
PMCID: PMC3096073  PMID: 21224735
Genetic testing; Missense mutations; Cancer susceptibility; Risk management; Cost effectiveness
8.  Sequence variant classification and reporting: recommendations for improving the interpretation of cancer susceptibility genetic test results 
Human mutation  2008;29(11):1282-1291.
Genetic testing of cancer susceptibility genes is now widely applied in clinical practice to predict risk of developing cancer. In general, sequence-based testing of germline DNA is used to determine whether an individual carries a change that is clearly likely to disrupt normal gene function. Genetic testing may detect changes that are clearly pathogenic, clearly neutral or variants of unclear clinical significance. Such variants present a considerable challenge to the diagnostic laboratory and the receiving clinician in terms of interpretation and clear presentation of the implications of the result to the patient. There does not appear to be a consistent approach to interpreting and reporting the clinical significance of variants either among genes or among laboratories. The potential for confusion among clinicians and patients is considerable and misinterpretation may lead to inappropriate clinical consequences. In this article we review the current state of sequence-based genetic testing, describe other standardized reporting systems used in oncology and propose a standardized classification system for application to sequence based results for cancer predisposition genes. We suggest a system of five classes of variants based on the degree of likelihood of pathogenicity. Each class is associated with specific recommendations for clinical management of at-risk relatives that will depend on the syndrome. We propose that panels of experts on each cancer predisposition syndrome facilitate the classification scheme and designate appropriate surveillance and cancer management guidelines. The international adoption of a standardized reporting system should improve the clinical utility of sequence-based genetic tests to predict cancer risk.
PMCID: PMC3075918  PMID: 18951446
IARC; variants; cancer genetics; classification; recommendations
9.  Long-term risk of medical conditions associated with breast cancer treatment 
Early and late effects of cancer treatment are of increasing concern with growing survivor populations, but relevant data are sparse. We sought to determine the prevalence and hazard ratio of such effects in breast cancer cases.
Patients and Methods
Women with invasive breast cancer and women with no cancer history recruited for a cancer research cohort completed a mailed questionnaire at a median of 10 years post-diagnosis or matched reference year (for the women without cancer). Reported medical conditions including lymphedema, osteopenia, osteoporosis, or heart disease (congestive heart failure, myocardial infarction, coronary heart disease) were assessed in relation to breast cancer therapy and time since diagnosis using Cox regression. The proportion of women currently receiving treatment for these conditions was calculated.
Study participants included 2535 women with breast cancer and 2428 women without cancer (response rates 66.0% and 50.4%, respectively) Women with breast cancer had an increased risk of lymphedema (Hazard ratio (HR) 8.6; 95% confidence interval (CI) 6.3-11.6), osteopenia (HR 2.1; 95% CI 1.8-2.4), and osteoporosis (HR 1.5; 95% CI 1.2-1.9) but not heart disease, as compared to women without cancer Hazard ratios varied by treatment and time since diagnosis. Overall, 49.3% of breast cancer cases reported at least one medical condition, and at 10 or more years post-diagnosis, 37.7% were currently receiving condition-related treatment.
Responses from survivors a decade following cancer diagnosis demonstrate substantial treatment-related morbidity, and emphasize the need for continued medical surveillance and follow-up care into the second decade post diagnosis.
PMCID: PMC4096572  PMID: 24696430
Breast Neoplasms; Lymphedema; Osteoporosis; Heart Disease; Chemotherapy; Radiotherapy
10.  Family history of cancer and childhood rhabdomyosarcoma: a report from the Children's Oncology Group and the Utah Population Database 
Cancer Medicine  2015;4(5):781-790.
Relatively little is known about the epidemiology and factors underlying susceptibility to childhood rhabdomyosarcoma (RMS). To better characterize genetic susceptibility to childhood RMS, we evaluated the role of family history of cancer using data from the largest case–control study of RMS and the Utah Population Database (UPDB). RMS cases (n = 322) were obtained from the Children's Oncology Group (COG). Population-based controls (n = 322) were pair-matched to cases on race, sex, and age. Conditional logistic regression was used to evaluate the association between family history of cancer and childhood RMS. The results were validated using the UPDB, from which 130 RMS cases were identified and matched to controls (n = 1300) on sex and year of birth. The results were combined to generate summary odds ratios (ORs) and 95% confidence intervals (CI). Having a first-degree relative with a cancer history was more common in RMS cases than controls (ORs = 1.39, 95% CI: 0.97–1.98). Notably, this association was stronger among those with embryonal RMS (ORs = 2.44, 95% CI: 1.54–3.86). Moreover, having a first-degree relative who was younger at diagnosis of cancer (<30 years) was associated with a greater risk of RMS (ORs = 2.37, 95% CI: 1.34–4.18). In the largest analysis of its kind, we found that most children diagnosed with RMS did not have a family history of cancer. However, our results indicate an increased risk of RMS (particularly embryonal RMS) in children who have a first-degree relative with cancer, and among those whose relatives were diagnosed with cancer at <30 years of age.
PMCID: PMC4430270  PMID: 25809884
Childhood cancer; epidemiology; family history; rhabdomyosarcoma; soft tissue sarcoma
11.  Molecular Findings Among Patients Referred for Clinical Whole-Exome Sequencing 
JAMA  2014;312(18):1870-1879.
Clinical whole-exome sequencing is increasingly used for diagnostic evaluation of patients with suspected genetic disorders.
To perform clinical whole-exome sequencing and report (1) the rate of molecular diagnosis among phenotypic groups, (2) the spectrum of genetic alterations contributing to disease, and (3) the prevalence of medically actionable incidental findings such as FBN1 mutations causing Marfan syndrome.
Observational study of 2000 consecutive patients with clinical whole-exome sequencing analyzed between June 2012 and August 2014. Whole-exome sequencing tests were performed at a clinical genetics laboratory in the United States. Results were reported by clinical molecular geneticists certified by the American Board of Medical Genetics and Genomics. Tests were ordered by the patient’s physician. The patients were primarily pediatric (1756 [88%]; mean age, 6 years; 888 females [44%], 1101 males [55%], and 11 fetuses [1% gender unknown]), demonstrating diverse clinical manifestations most often including nervous system dysfunction such as developmental delay.
Whole-exome sequencing diagnosis rate overall and by phenotypic category, mode of inheritance, spectrum of genetic events, and reporting of incidental findings.
A molecular diagnosis was reported for 504 patients (25.2%) with 58% of the diagnostic mutations not previously reported. Molecular diagnosis rates for each phenotypic category were 143/526 (27.2%; 95% CI, 23.5%–31.2%) for the neurological group, 282/1147 (24.6%; 95% CI, 22.1%–27.2%) for the neurological plus other organ systems group, 30/83 (36.1%; 95% CI, 26.1%–47.5%) for the specific neurological group, and 49/244 (20.1%; 95% CI, 15.6%–25.8%) for the nonneurological group. The Mendelian disease patterns of the 527 molecular diagnoses included 280 (53.1%) autosomal dominant, 181 (34.3%) autosomal recessive (including 5 with uniparental disomy), 65 (12.3%) X-linked, and 1 (0.2%) mitochondrial. Of 504 patients with a molecular diagnosis, 23 (4.6%) had blended phenotypes resulting from 2 single gene defects. About 30% of the positive cases harbored mutations in disease genes reported since 2011. There were 95 medically actionable incidental findings in genes unrelated to the phenotype but with immediate implications for management in 92 patients (4.6%), including 59 patients (3%) with mutations in genes recommended for reporting by the American College of Medical Genetics and Genomics.
Whole-exome sequencing provided a potential molecular diagnosis for 25% of a large cohort of patients referred for evaluation of suspected genetic conditions, including detection of rare genetic events and new mutations contributing to disease. The yield of whole-exome sequencing may offer advantages over traditional molecular diagnostic approaches in certain patients.
PMCID: PMC4326249  PMID: 25326635
12.  Targeted Sequencing in Chromosome 17q Linkage Region Identifies Familial Glioma Candidates in the Gliogene Consortium 
Scientific Reports  2015;5:8278.
Glioma is a rare, but highly fatal, cancer that accounts for the majority of malignant primary brain tumors. Inherited predisposition to glioma has been consistently observed within non-syndromic families. Our previous studies, which involved non-parametric and parametric linkage analyses, both yielded significant linkage peaks on chromosome 17q. Here, we use data from next generation and Sanger sequencing to identify familial glioma candidate genes and variants on chromosome 17q for further investigation. We applied a filtering schema to narrow the original list of 4830 annotated variants down to 21 very rare (<0.1% frequency), non-synonymous variants. Our findings implicate the MYO19 and KIF18B genes and rare variants in SPAG9 and RUNDC1 as candidates worthy of further investigation. Burden testing and functional studies are planned.
PMCID: PMC4317686  PMID: 25652157
13.  Defective mitochondrial peroxiredoxin-3 results in sensitivity to oxidative stress in Fanconi anemia 
The Journal of Cell Biology  2006;175(2):225-235.
Cells from patients with Fanconi anemia (FA), an inherited disorder that includes bone marrow failure and cancer predisposition, have increased sensitivity to oxidative stress through an unknown mechanism. We demonstrate that the FA group G (FANCG) protein is found in mitochondria. Wild-type but not G546R mutant FANCG physically interacts with the mitochondrial peroxidase peroxiredoxin-3 (PRDX3). PRDX3 is deregulated in FA cells, including cleavage by a calpainlike cysteine protease and mislocalization. FA-G cells demonstrate distorted mitochondrial structures, and mitochondrial extracts have a sevenfold decrease in thioredoxin-dependent peroxidase activity. Transient overexpression of PRDX3 suppresses the sensitivity of FA-G cells to H2O2, and decreased PRDX3 expression increases sensitivity to mitomycin C. Cells from the FA-A and -C subtypes also have PRDX3 cleavage and decreased peroxidase activity. This study demonstrates a role for the FA proteins in mitochondria witsh sensitivity to oxidative stress resulting from diminished peroxidase activity. These defects may lead to apoptosis and the accumulation of oxidative DNA damage in bone marrow precursors.
PMCID: PMC2064564  PMID: 17060495
14.  Experiences and Attitudes of Genome Investigators Regarding Return of Individual Genetic Test Results 
Whether and how to return individual genetic results to study participants is among the most contentious policy issues in contemporary genomic research.
We surveyed corresponding authors of genome-wide association studies (GWAS), identified through the National Human Genome Research Institute's Catalog of Published GWAS, to describe the experiences and attitudes of these stakeholders.
Of 357 corresponding authors, 200 (56%) responded. One hundred twenty-six (63%) had been responsible for primary data and sample collection, whereas 74 (37%) had performed secondary analyses. Only 7 (4%) had returned individual results within their index GWAS. Most (69%) believed that return of results to individual participants was warranted under at least some circumstances. Most respondents identified a desire to benefit participants's health (63%) and respect for participants's; desires for information (57%) as major motivations for returning results. Most also identified uncertain clinical utility (76%), the possibility that participants will misunderstand results (74%), the potential for emotional harm (61%), the need to ensure access to trained clinicians (59%), and the potential for loss of confidentiality (51%) as major barriers to return.
Investigators have limited experience returning individual results from genome-scale research, yet most are motivated to do so in at least some circumstances.
PMCID: PMC4143384  PMID: 23639901
15.  Clinical Whole-Exome Sequencing for the Diagnosis of Mendelian Disorders 
The New England journal of medicine  2013;369(16):1502-1511.
Whole-exome sequencing is a diagnostic approach for the identification of molecular defects in patients with suspected genetic disorders.
We developed technical, bioinformatic, interpretive, and validation pipelines for whole-exome sequencing in a certified clinical laboratory to identify sequence variants underlying disease phenotypes in patients.
We present data on the first 250 probands for whom referring physicians ordered whole-exome sequencing. Patients presented with a range of phenotypes suggesting potential genetic causes. Approximately 80% were children with neurologic pheno-types. Insurance coverage was similar to that for established genetic tests. We identified 86 mutated alleles that were highly likely to be causative in 62 of the 250 patients, achieving a 25% molecular diagnostic rate (95% confidence interval, 20 to 31). Among the 62 patients, 33 had autosomal dominant disease, 16 had auto-somal recessive disease, and 9 had X-linked disease. A total of 4 probands received two nonoverlapping molecular diagnoses, which potentially challenged the clinical diagnosis that had been made on the basis of history and physical examination. A total of 83% of the autosomal dominant mutant alleles and 40% of the X-linked mutant alleles occurred de novo. Recurrent clinical phenotypes occurred in patients with mutations that were highly likely to be causative in the same genes and in different genes responsible for genetically heterogeneous disorders.
Whole-exome sequencing identified the underlying genetic defect in 25% of consecutive patients referred for evaluation of a possible genetic condition. (Funded by the National Human Genome Research Institute.)
PMCID: PMC4211433  PMID: 24088041
16.  Obtaining informed consent for clinical tumor and germline exome sequencing of newly diagnosed childhood cancer patients 
Genome Medicine  2014;6(9):69.
Effectively educating families about the risks and benefits of genomic tests such as whole exome sequencing (WES) offers numerous challenges, including the complexity of test results and potential loss of privacy. Research on best practices for obtaining informed consent (IC) in a variety of clinical settings is needed. The BASIC3 study of clinical tumor and germline WES in an ethnically diverse cohort of newly diagnosed pediatric cancer patients offers the opportunity to study the IC process in the setting of critical illness. We report on our experience for the first 100 families enrolled, including study participation rates, reasons for declining enrollment, assessment of clinical and demographic factors that might impact study enrollment, and preferences of parents for participation in optional genomics study procedures.
A specifically trained IC team offered study enrollment to parents of eligible children for procedures including clinical tumor and germline WES with results deposited in the medical record and disclosure of both diagnostic and incidental results to the family. Optional study procedures were also offered, such as receiving recessive carrier status and deposition of data into research databases. Stated reasons for declining participation were recorded. Clinical and demographic data were collected and comparisons made between enrolled and non-enrolled patients.
Over 15 months, 100 of 121 (83%) eligible families elected to enroll in the study. No significant differences in enrollment were detected based on factors such as race, ethnicity, use of Spanish interpreters and Spanish consent forms, and tumor features (central nervous system versus non-central nervous system, availability of tumor for WES). The most common reason provided for declining enrollment (10% of families) was being overwhelmed by the new cancer diagnosis. Risks specific to clinical genomics, such as privacy concerns, were less commonly reported (5.5%). More than 85% of parents consented to each of the optional study procedures.
An IC process was developed that utilizes a specialized IC team, active communication with the oncology team, and an emphasis on scheduling flexibility. Most parents were willing to participate in a clinical germline and tumor WES study as well as optional procedures such as genomic data sharing independent of race, ethnicity or language spoken.
Electronic supplementary material
The online version of this article (doi:10.1186/s13073-014-0069-3) contains supplementary material, which is available to authorized users.
PMCID: PMC4195891  PMID: 25317207
17.  Prediction of Missense Mutation Functionality Depends on both the Algorithm and Sequence Alignment Employed 
Human mutation  2011;32(6):661-668.
Multiple algorithms are used to predict the impact of missense mutations on protein structure and function using algorithm-generated sequence alignments or manually curated alignments. We compared the accuracy with native alignment of SIFT, Align-GVGD, PolyPhen-2 and Xvar when generating functionality predictions of well characterized missense mutations (n = 267) within the BRCA1, MSH2, MLH1 and TP53 genes. We also evaluated the impact of the alignment employed on predictions from these algorithms (except Xvar) when supplied the same four alignments including alignments automatically generated by (1) SIFT, (2) Polyphen-2, (3) Uniprot, and (4) a manually curated alignment tuned for Align-GVGD. Alignments differ in sequence composition and evolutionary depth. Data-based receiver operating characteristic curves employing the native alignment for each algorithm result in area under the curve of 78-79% for all four algorithms. Predictions from the PolyPhen-2 algorithm were least dependent on the alignment employed. In contrast, Align-GVGD predicts all variants neutral when provided alignments with a large number of sequences. Of note, algorithms make different predictions of variants even when provided the same alignment and do not necessarily perform best using their own alignment. Thus, researchers should consider optimizing both the algorithm and sequence alignment employed in missense prediction.
PMCID: PMC4154965  PMID: 21480434
multiple sequence alignment; SIFT; PolyPhen-2; Align-GVGD; Xvar; BRCA1; MSH2; MLH1; TP53
18.  Genomic profiling in Down syndrome acute lymphoblastic leukemia identifies histone gene deletions associated with altered methylation profiles 
Leukemia  2011;25(10):1555-1563.
Patients with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) have distinct clinical and biological features. Whereas most DS-ALL cases lack the sentinel cytogenetic lesions that guide risk assignment in childhood ALL, JAK2 mutations and CRLF2 overexpression are highly enriched. To further characterize the unique biology of DS-ALL, we performed genome-wide profiling of 58 DS-ALL and 68 non-Down syndrome (NDS) ALL cases by DNA copy number, loss of heterozygosity, gene expression, and methylation analyses. We report a novel deletion within the 6p22 histone gene cluster as significantly more frequent in DS-ALL, occurring in 11 DS (22%) and only two NDS cases (3.1%) (Fisher’s exact p = 0.002). Homozygous deletions yielded significantly lower histone expression levels, and were associated with higher methylation levels, distinct spatial localization of methylated promoters, and enrichment of highly methylated genes for specific pathways and transcription factor binding motifs. Gene expression profiling demonstrated heterogeneity of DS-ALL cases overall, with supervised analysis defining a 45-transcript signature associated with CRLF2 overexpression. Further characterization of pathways associated with histone deletions may identify opportunities for novel targeted interventions.
PMCID: PMC4107887  PMID: 21647151
Down syndrome; acute lymphoblastic leukemia (ALL); histone; JAK2; CRLF2
19.  Clinical Utility of Array Comparative Genomic Hybridization for Detection of Chromosomal Abnormalities in Pediatric Acute Lymphoblastic Leukemia 
Pediatric blood & cancer  2008;51(2):171-177.
Accurate detection of recurrent chromosomal abnormalities is critical to assign patients to risk-based therapeutic regimens for pediatric acute lymphoblastic leukemia (ALL).
We investigated the utility of array comparative genomic hybridization (aCGH) for detection of chromosomal abnormalities compared to standard clinical evaluation with karyotype and fluorescent in-situ hybridization (FISH). Fifty pediatric ALL diagnostic bone marrows were analyzed by bacterial artificial chromosome (BAC) array, and findings compared to standard clinical evaluation.
Sensitivity of aCGH was 79% to detect karyotypic findings other than balanced translocations, which cannot be detected by aCGH because they involve no copy number change. aCGH also missed abnormalities occurring in subclones constituting less than 25% of cells. aCGH detected 44 additional abnormalities undetected or misidentified by karyotype, 21 subsequently validated by FISH, including abnormalities in 4 of 10 cases with uninformative cytogenetics. aCGH detected concurrent terminal deletions of both 9p and 20q in three cases, in two of which the 20q deletion was undetected by karyotype. A narrow region of loss at 7p21 was detected in two cases.
An array with increased BAC density over regions important in ALL, combined with PCR for fusion products of balanced translocations, could minimize labor- and time-intensive cytogenetic assays and provide key prognostic information in the approximately 35% of cases with uninformative cytogenetics.
PMCID: PMC4063297  PMID: 18253961
Array comparative genomic hybridization (aCGH); acute lymphoblastic leukemia (ALL)
20.  BRCA1/2 Sequence Variants of Uncertain Significance: A Primer for Providers to Assist in Discussions and in Medical Management 
The Oncologist  2013;18(5):518-524.
DNA variants of uncertain significance are common outcomes of testing for susceptibility to cancer. A statistically rigorous model that provides a pathogenicity score for each variant has been developed to aid in the clinical management of patients undergoing genetic testing. The pathogenicity score that is generated by this model maps to the IARC system for clinical management, which will assist clinicians in the medical management of those patients who obtain a VAS result upon testing.
DNA variants of uncertain significance (VUS) are common outcomes of clinical genetic testing for susceptibility to cancer. A statistically rigorous model that provides a pathogenicity score for each variant has been developed to aid in the clinical management of patients undergoing genetic testing.
The information in this article is derived from multiple publications on VUS in BRCA genes, distilled for communicating with clinicians who may encounter VUS in their practice.
The posterior probability scores for BRCA1 or BRCA2 VUS, calculated from a multifactorial likelihood model, are explained, and links for looking up specific VUS are provided. The International Agency on Cancer Research (IARC) of the World Health Organization has proposed a simple five-tier system for clinical management that is not widely known to clinicians. Classes 1 and 2 in this system are managed as neutral variants, classes 4 and 5 are managed as pathogenic variants, and class 3 variants still have insufficient evidence to move to either end of this scale and, thus, cannot be used in medical management.
Development of models that integrate multiple independent lines of evidence has allowed classification of a growing number of VUS in the BRCA1 and BRCA2 genes. The pathogenicity score that is generated by this model maps to the IARC system for clinical management, which will assist clinicians in the medical management of those patients who obtain a VUS result upon testing.
PMCID: PMC3662842  PMID: 23615697
BRCA1; BRCA2; Counseling; Likelihood; Management; Multifactorial
21.  Unusually early presentation of small-bowel adenocarcinoma in a patient with Peutz-Jeghers syndrome 
Peutz-Jeghers (PJS) syndrome is an autosomal dominant cancer predisposition syndrome characterized by melanotic macules, and hamartomatous polyps. Small-bowel surveillance in the pediatric PJS population is not designed to identify small-bowel malignancy which is thought to arise in adulthood. A 13 year old male presented with lead-point intussusception, requiring emergent surgical resection. A mucinous adenocarcinoma was found arising from high-grade dysplasia within a polyp. Based on these findings and mucosal pigmentation he was diagnosed with PJS. DNA sequencing revealed a heterozygous c.921-1G>T STK11 mutation. This case is the earliest onset of small-bowel carcinoma in PJS, an observation relevant to surveillance guidelines.
PMCID: PMC3708690  PMID: 23426006
Peutz-Jeghers syndrome; STK11; small-bowel adenocarcinoma; lead-point intusussception; cancer surveillance
22.  Identification of a recurrent germline PAX5 mutation and susceptibility to pre-B cell acute lymphoblastic leukemia 
Nature genetics  2013;45(10):1226-1231.
PMCID: PMC3919799  PMID: 24013638
23.  A survey of informatics approaches to whole-exome and whole-genome clinical reporting in the electronic health record 
Genome-scale clinical sequencing is being adopted more broadly in medical practice. The National Institutes of Health developed the Clinical Sequencing Exploratory Research (CSER) program to guide implementation and dissemination of best practices for the integration of sequencing into clinical care. This study describes and compares the state of the art of incorporating whole-exome and whole-genome sequencing results into the electronic health record, including approaches to decision support across the six current CSER sites.
The CSER Medical Record Working Group collaboratively developed and completed an in-depth survey to assess the communication of genome-scale data into the electronic health record. We summarized commonalities and divergent approaches.
Despite common sequencing platform (Illumina) adoptions, there is a great diversity of approaches to annotation tools and workflow, as well as to report generation. At all sites, reports are human-readable structured documents available as passive decision support in the electronic health record. Active decision support is in early implementation at two sites.
The parallel efforts across CSER sites in the creation of systems for report generation and integration of reports into the electronic health record, as well as the lack of standardized approaches to interfacing with variant databases to create active clinical decision support, create opportunities for cross-site and vendor collaborations.
PMCID: PMC3951437  PMID: 24071794
clinical decision support; clinical sequencing; decision support rules; electronic health record; electronic medical record; next-generation sequencing
24.  Next Generation Sequencing in the Clinic: Are we Ready? 
Nature reviews. Genetics  2012;13(11):818-824.
PMCID: PMC3891793  PMID: 23076269
25.  Returning genetic research results: study type matters 
Personalized medicine  2013;10(1):27-34.
The return of individual genetic research results has been identified as one of the most pressing ethical challenges warranting immediate policy attention. We explored the practices and perspectives of genome-wide association studies (GWAS) investigators on this topic.
Materials & methods
Corresponding authors of published GWAS were invited to participate in a semistructured interview. Interviews (n = 35) were transcribed and analyzed using conventional content analysis.
Most investigators had not returned GWAS results. Several had experience returning results in the context of linkage/family studies, and many felt that it will become a larger issue in whole-genome/-exome sequencing.
Research context and nature of the study are important considerations in the decision to return results. More nuanced ethical guidelines should take these contextual factors into account.
PMCID: PMC3783351  PMID: 24077424
ethics; genome-wide association; genomics; policy; return of results; whole-genome sequencing

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