Families' experiences accessing care after genomic sequencing in the pediatric cancer context: "It's just been a big juggle".

Access to genomic sequencing (GS) and resulting recommendations have not been well described in pediatric oncology. GS results may provide a cancer predisposition syndrome (CPS) diagnosis that warrants screening and specialist visits beyond cancer treatment, including testing or surveillance for family members. The Texas KidsCanSeq (KCS) Study evaluated implementation of GS in a diverse pediatric oncology population. We conducted semi-structured interviews (n = 20) to explore experiences of KCS patients' families around learning about a CPS diagnosis and following up on recommended care. We used qualitative content analysis to develop themes and subthemes across families' descriptions of their experiences accessing care and to understand which factors presented barriers and/or facilitators. We found participants had difficulty differentiating which follow-up care recommendations were made for their child's current cancer treatment versus the CPS. In families' access to follow-up care for CPS, organizational factors were crucial: travel time and distance were common hardships, while coordination of care to streamline multiple appointments with different providers helped facilitate CPS care. Financial factors also impacted families' access to CPS-related follow-up care: having financial assistance and insurance were facilitators for families, while costs and lack of insurance posed as barriers for patients who lost coverage during transitions from pediatric to adult care, and for adult family members who had no coverage. Factors related to beliefs and perceptions, specifically perceiving the risk as less salient to them and feeling overwhelmed with the patient's cancer care, presented barriers to follow-up care primarily for family members. Regarding social factors, competing life priorities made it difficult for families to access follow-up care, though having community support alleviated these barriers. We suggest interventions to improve coordination of cancer treatment and CPS-related care and adherence to surveillance protocols for families as children age, such as care navigators and integrating longitudinal genetic counseling into hereditary cancer centers.

Circulating tumor DNA sequencing of pediatric solid and brain tumor patients: An institutional feasibility study.

The potential of circulating tumor DNA (ctDNA) analysis to serve as a real-time "liquid biopsy" for children with central nervous system (CNS) and non-CNS solid tumors remains to be fully elucidated. We conducted a study to investigate the feasibility and potential clinical utility of ctDNA sequencing in pediatric patients enrolled on an institutional clinical genomics trial. A total of 240 patients had tumor DNA profiling performed during the study period. Plasma samples were collected at study enrollment from 217 patients and then longitudinally from a subset of patients. Successful cell-free DNA extraction and quantification occurred in 216 of 217 (99.5%) of these initial samples. Twenty-four patients were identified whose tumors harbored 30 unique variants that were potentially detectable on a commercially-available ctDNA panel. Twenty of these 30 mutations (67%) were successfully detected by next-generation sequencing in the ctDNA from at least one plasma sample. The rate of ctDNA mutation detection was higher in patients with non-CNS solid tumors (7/9, 78%) compared to those with CNS tumors (9/15, 60%). A higher ctDNA mutation detection rate was also observed in patients with metastatic disease (9/10, 90%) compared to non-metastatic disease (7/14, 50%), although tumor-specific variants were detected in a few patients in the absence of radiographic evidence of disease. This study illustrates the feasibility of incorporating longitudinal ctDNA analysis into the management of relapsed or refractory patients with childhood CNS or non-CNS solid tumors.

Genetic markers for treatment-related pancreatitis in a cohort of Hispanic children with acute lymphoblastic leukemia.

PURPOSE: Treatment-related pancreatitis (TRP) is a serious complication occurring in children with acute lymphoblastic leukemia (ALL). Those affected are at high risk for severe organ toxicity and treatment delays that can impact outcomes. TRP is associated with asparaginase, a standard therapeutic agent in childhood ALL. Native American ancestry, older age, high-risk leukemia, and increased use of asparaginase are linked to pancreatitis risk. However, dedicated genetic studies evaluating pancreatitis in childhood ALL include few Hispanics. Thus, the genetic basis for higher risk of pancreatitis among Hispanic children with ALL remains unknown. METHODS: Cases of children with ALL treated in from 1994 through 2013 were reviewed and identified 14, all Hispanic, who developed pancreatitis related to asparaginase therapy. Forty-six controls consisting of Hispanic children treated on the same regimens without pancreatitis were selected for comparison. Total DNA isolated from whole blood was used for targeted DNA sequencing of 23 selected genes, including genes associated with pancreatitis without ALL and genes involved in asparagine metabolism. RESULTS: Non-synonymous polymorphisms and frameshift deletions were detected in 15 genes. Most children with TRP had variants in ABAT, ASNS, and CFTR. Notably, children with TRP harbored many more CFTR variants (71.4%) compared with controls (39.1%). Among these, V470M (rs213950) was most frequent (OR 4.27, p = 0.025). CONCLUSIONS: This is the first study of genetic factors in treatment-related pancreatitis in Hispanic children with ALL. Identifying correlative variants in ethnically vulnerable populations may improve screening to identify which patients with ALL are at greatest risk for pancreatitis.

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. 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, and 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 2,535 women with breast cancer and 2,428 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, 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.

Neonatal medical exposures and characteristics of low birth weight hepatoblastoma cases: a report from the Children's Oncology Group.

BACKGROUND: Hepatoblastoma is a malignancy of young children. Low birth weight is associated with significantly increased risk of hepatoblastoma and neonatal medical exposures are hypothesized as contributors. This study represents the largest case-control study of hepatoblastoma to date and aimed to define the role of neonatal exposures in hepatoblastoma risk among low birth weight children. PROCEDURE: Incident hepatoblastoma cases who were born <2,500 g (N = 60), diagnosed between 2000 and 2008, were identified through the Children's Oncology Group. Controls were recruited through state birth registries (N = 51). Neonatal medical exposures were abstracted from medical records. Subjects from the Vermont Oxford Network were used for further comparisons, as were existing reports on neonatal medical exposures. RESULTS: Case-control comparisons were hindered by poor matching within birth weight strata. Cases were smaller and received more aggressive neonatal treatment compared to controls, and reflected high correlation levels between birth weight and treatments. Similar difficulty was encountered when comparing cases to Vermont Oxford Network subjects; cases were smaller and required more aggressive neonatal therapy. Furthermore, it appears hepatoblastoma cases were exposed to a greater number of diagnostic X-rays than in case series previously reported in the neonatal literature. CONCLUSIONS: This study presents the largest case series of hepatoblastoma in <2,500 g birth weight infants with accompanying neonatal medical exposure data. Findings confirm that birth weight is highly correlated with exposure intensity, and neonatal exposures are themselves highly correlated, which hampers the identification of a causal exposure among hepatoblastoma cases. Experimental models or genetic susceptibility testing may be more revealing of etiology.

Correction: Childhood cancer survival in the highly vulnerable population of South Texas: A cohort study.

[This corrects the article DOI: 10.1371/journal.pone.0278354.].

Clinical, histologic, and genetic features of mesothelioma in a 7-year-old child.

Malignant mesothelioma (MM) is a highly aggressive malignancy that is extremely rare in children. This case report documents a 7-year-old male without previous asbestos exposure with peritoneal MM that initially responded to chemotherapy with cisplatin and gemcitabine but ultimately metastasized to his chest. He was diagnosed with MM based on histology, extensive immunohistochemical analyses, and an elevated serum CA-125 level. Cytogenetics and comparative genomic hybridization (CGH) analysis of his tumor identified a single extra copy number of chromosome 11 with few other changes noted.

Outcomes for patients with congenital hepatoblastoma.

BACKGROUND: Congenital hepatoblastoma, diagnosed in the first month of life, has been reported to have a poor prognosis; however, a comprehensive evaluation of this entity is lacking. PROCEDURE: We retrospectively reviewed two patients from the senior authors' personal series and 25 cases identified in the databases of several multicenter group studies (INT-0098, P9645, 881, P9346, HB 89, HB94, and HB 99). We compared this series with cases of congenital hepatoblastoma previously published in the literature. RESULTS: The 3-year survival in our case series was 86% (18/21) with a follow-up of 44-230 months (median 85.5 months). Presentation and treatment were not substantially different from hepatoblastoma cohorts unselected for age. Survival was comparable to the reported disease free survival for a similar cohort of hepatoblastoma patients unselected for age between 1986 and 2002 (82.5%) [von Schweinitz et al., Eur J Cancer 1997; 33:1243-1249]. The 2-year survival of cases reported in the literature was 0% (0/9) and 42% (10/24) for patients reported before and after 1990, respectively. CONCLUSIONS: Congenital hepatoblastoma does not appear to confer a worse prognosis. The improved survival of our current series of patients, collected from the past 20 years of German and American multicenter trials and personal series, suggests that the outcome of hepatoblastoma at this young age is much better than has been historically reported. More rigorous analysis should be conducted in future multicenter trials. It is possible that congenital hepatoblastoma should be treated like all other patients with hepatoblastoma provided that the child is stable enough to proceed with surgery and chemotherapy.

Childhood cancer survival in the highly vulnerable population of South Texas: A cohort study.

This study examines childhood cancer survival rates and prognostic factors related to survival in the majority Hispanic population of South Texas. The population-based cohort study used Texas Cancer Registry data (1995-2017) to examine survival and prognostic factors. Cox proportional hazard models and Kaplan-Meier survival curves were used for survival analyses. The 5-year relative survival rate for 7,999 South Texas cancer patients diagnosed at 0-19 years was 80.3% for all races/ethnicities. Hispanic patients had statistically significant lower 5-year relative survival rates than non-Hispanic White (NHW) patients for male and female together diagnosed at age≥5 years. When comparing survival among Hispanic and NHW patients for the most common cancer, acute lymphocytic leukemia (ALL), the difference was most significant in the 15-19 years age range, with 47.7% Hispanic patients surviving at 5 years compared to 78.4% of NHW counterparts. The multivariable-adjusted analysis showed that males had statistically significant 13% increased mortality risk than females [hazard ratio (HR): 1.13, 95% confidence interval (CI):1.01-1.26] for all cancer types. Comparing to patients diagnosed at ages 1-4 years, patients diagnosed at age < 1 year (HR: 1.69, 95% CI: 1.36-2.09), at 10-14 year (HR: 1.42, 95% CI: 1.20-1.68), or at 15-19 years (HR: 1.40, 95% CI: 1.20-1.64) had significant increased mortality risk. Comparing to NHW patients, Hispanic patients showed 38% significantly increased mortality risk for all cancer types, 66% for ALL, and 52% for brain cancer. South Texas Hispanic patients had lower 5-year relative survival than NHW patients especially for ALL. Male gender, diagnosis at age<1 year or 10-19 years were also associated with decreased childhood cancer survival. Despite advances in treatment, Hispanic patients lag significantly behind NHW patients. Further cohort studies in South Texas are warranted to identify additional factors affecting survival and to develop interventional strategies.

Defining function of wild-type and three patient-specific TP53 mutations in a zebrafish model of embryonal rhabdomyosarcoma.

In embryonal rhabdomyosarcoma (ERMS) and generally in sarcomas, the role of wild-type and loss- or gain-of-function TP53 mutations remains largely undefined. Eliminating mutant or restoring wild-type p53 is challenging; nevertheless, understanding p53 variant effects on tumorigenesis remains central to realizing better treatment outcomes. In ERMS, >70% of patients retain wild-type TP53, yet mutations when present are associated with worse prognosis. Employing a kRASG12D-driven ERMS tumor model and tp53 null (tp53-/-) zebrafish, we define wild-type and patient-specific TP53 mutant effects on tumorigenesis. We demonstrate that tp53 is a major suppressor of tumorigenesis, where tp53 loss expands tumor initiation from <35% to >97% of animals. Characterizing three patient-specific alleles reveals that TP53C176F partially retains wild-type p53 apoptotic activity that can be exploited, whereas TP53P153Δ and TP53Y220C encode two structurally related proteins with gain-of-function effects that predispose to head musculature ERMS. TP53P153Δ unexpectedly also predisposes to hedgehog-expressing medulloblastomas in the kRASG12D-driven ERMS-model.

Comprehensive characterization of patient-derived xenograft models of pediatric leukemia.

Patient-derived xenografts (PDX) remain valuable models for understanding the biology and for developing novel therapeutics. To expand current PDX models of childhood leukemia, we have developed new PDX models from Hispanic patients, a subgroup with a poorer overall outcome. Of 117 primary leukemia samples obtained, successful engraftment and serial passage in mice were achieved in 82 samples (70%). Hispanic patient samples engrafted at a rate (51/73, 70%) that was similar to non-Hispanic patient samples (31/45, 70%). With a new algorithm to remove mouse contamination in multi-omics datasets including methylation data, we found PDX models faithfully reflected somatic mutations, copy-number alterations, RNA expression, gene fusions, whole-genome methylation patterns, and immunophenotypes found in primary tumor (PT) samples in the first 50 reported here. This cohort of characterized PDX childhood leukemias represents a valuable resource in that germline DNA sequencing has allowed the unambiguous determination of somatic mutations in both PT and PDX.

Genomic profiling of subcutaneous patient-derived xenografts reveals immune constraints on tumor evolution in childhood solid cancer.

Subcutaneous patient-derived xenografts (PDXs) are an important tool for childhood cancer research. Here, we describe a resource of 68 early passage PDXs established from 65 pediatric solid tumor patients. Through genomic profiling of paired PDXs and patient tumors (PTs), we observe low mutational similarity in about 30% of the PT/PDX pairs. Clonal analysis in these pairs show an aggressive PT minor subclone seeds the major clone in the PDX. We show evidence that this subclone is more immunogenic and is likely suppressed by immune responses in the PT. These results suggest interplay between intratumoral heterogeneity and antitumor immunity may underlie the genetic disparity between PTs and PDXs. We further show that PDXs generally recapitulate PTs in copy number and transcriptomic profiles. Finally, we report a gene fusion LRPAP1-PDGFRA. In summary, we report a childhood cancer PDX resource and our study highlights the role of immune constraints on tumor evolution.

Heat shock protein 90 regulates the expression of Wilms tumor 1 protein in myeloid leukemias.

The aberrant overexpression of Wilms tumor 1 (WT1) in myeloid leukemia plays an important role in blast cell survival and resistance to chemotherapy. High expression of WT1 is also associated with relapse and shortened disease-free survival in patients. However, the mechanisms by which WT1 expression is regulated in leukemia remain unclear. Here, we report that heat shock protein 90 (Hsp90), which plays a critical role in the folding and maturation of several oncogenic proteins, associates with WT1 protein and stabilizes its expression. Pharmacologic inhibition of Hsp90 resulted in ubiquitination and subsequent proteasome-dependant degradation of WT1. RNAi-mediated silencing of WT1 reduced the survival of leukemia cells and increased the sensitivity of these cells to chemotherapy and Hsp90 inhibition. Furthermore, Hsp90 inhibitors 17-AAG [17-(allylamino)-17-demethoxygeldanamycin] and STA-9090 significantly reduced the growth of myeloid leukemia xenografts in vivo and effectively down-regulated the expression of WT1 and its downstream target proteins, c-Myc and Bcl-2. Collectively, our studies identify WT1 as a novel Hsp90 client and support the crucial role for the WT1-Hsp90 interaction in maintaining leukemia cell survival. These findings have significant implications for developing effective therapies for myeloid leukemias and offer a strategy to inhibit the oncogenic functions of WT1 by clinically available Hsp90 inhibitors.

Parental infertility, infertility treatment and hepatoblastoma: a report from the Children's Oncology Group.

BACKGROUND: A recent study suggested a markedly increased risk of hepatoblastoma (HB) among children conceived with treatment for infertility. However, it is not clear whether this finding is confounded by the association between HB and low birthweight (LBW). METHODS: Associations between parental infertility and its treatment and HB were examined using data from a case-control study conducted through the Children's Oncology Group (COG). Telephone interviews were completed for 383 mothers of cases diagnosed with HB at US COG institutions between January 2000 and December 2008 and for 387 mothers of controls recruited through state birth registries. Logistic regression was used to examine possible associations. RESULTS: After adjusting for birthweight and other potential confounders, no significant association was found for any of the measures of parental infertility or its treatment. In HB cases conceived through assisted reproductive technology (ART), 4 of 16 also had Beckwith-Wiedemann syndrome (BWS) compared with 9 of 365 in HB cases without ART. CONCLUSIONS: Little evidence of an association between parental infertility or its treatment and HB was found. The relationship found in a previous study could be due to LBW and BWS which are risk factors for HB and also associated with parental infertility and its treatment.

Genetics and epigenetics of hepatoblastoma.

A number of unique genetic features are observed in hepatoblastoma that have provided insights into the origins of hepatoblastoma. Hallmark cytogenetic changes in hepatoblastoma include the acquisition of additional copies of whole chromosomes and a recurring unbalanced translocation involving 1q. Genetic syndromes are associated with approximately 15% of hepatoblastoma and the understanding and recognition of these syndromes will be important in determining future surveillance studies needed to prevent additional cancers in survivors as well as in some case guide the care of family members. This article will review the genetic changes, both germ line and acquired, that are recurring events in hepatoblastoma, with emphasis on how these genetic changes could work together with other developmental factors and influence cancer predisposition, tumor growth, as well as aid in prognosis. Tumor-specific signatures based on transcriptional or epigenetic alterations will be reviewed that might be used in the future to better diagnose and subtype the disease as well as predict prognosis and response to therapy.

ETV6-NTRK3--Trk-ing the primary event in human secretory breast cancer.

In this issue of Cancer Cell, propose a single chromosomal translocation as the cause of a particularly troubling form of breast cancer, secretory carcinoma. They challenge widely held beliefs concerning breast carcinogenesis as well as beliefs concerning the absolute association of specific fusion genes with specific tumor types. Their data highlight the role of Trk signaling in breast cancer and also suggest a target for drug development.

Prevalence of pathogenic germline cancer risk variants in testicular cancer patients: Identifying high risk groups.

BACKGROUND: Germline studies in testicular cancer have focused on unselected populations but so far have not led to recommendations for testicular cancer screening. OBJECTIVE: Herein, we hypothesized that men with testicular cancer and an additional risk factor for hereditary cancer predisposition carry a higher rate of pathogenic variants than men with testicular cancer without another risk factor. METHODS AND RESULTS: 187 patients with a personal history of testicular cancer underwent germline testing via Invitae. Patients were divided into low-risk and high-risk patients. Low-risk patients (n=83) had testicular cancer as their only primary malignancy without a family history of testicular cancer. High-risk patients (n=104) had additional primary malignancies and/or a family history of testicular cancer. 23.1% of patients harbored pathogenic germline variants with 19.6% carrying actionable variants. Among low-risk patients, 13.5% carried pathogenic variants versus 29.9% in the high-risk cohort. Of patients with a family history of non-testicular cancers and a personal history of additional primary malignancies, 32% harbored pathogenic variants. CONCLUSION: High-risk patients are twice as likely to harbor pathogenic variants compared to low-risk patients. Importantly, patients with a family history of cancer and other primary malignancies represent a subset of patients that may benefit from genetic evaluation.

Disparities in Cancer Genetic Testing and Variants of Uncertain Significance in the Hispanic Population of South Texas.

PURPOSE: Racial and ethnic disparities have included a lack of access to both genetic testing and research, resulting in poor understanding of the genomic architecture in under-represented populations. The South Texas population is primarily of Hispanic background and has been largely devoid of genetic services. We extended access to this underserved population and uncovered genetic variants previously not observed, emphasizing the need to continually improve both genomic databases and clarification of variant significance to provide meaningful patient counseling. METHODS: This study consisted of a retrospective cohort review of patients seen through a cancer genetics education and service program across 24 counties in South Texas. In total, 1,595 individuals were identified as appropriate for cancer genetic counseling and 1,377 completed genetic testing. RESULTS: Eighty percent of those receiving genetic counseling self-identified as Hispanic, 16% as non-Hispanic White (NHW), 3% as African American, and 1% as other race/ethnicity. Of reported variants, 18.8% were pathogenic and 13.7% were reported as a variant of uncertain significance (VUS). VUS was reported in 17.2% of the Hispanic individuals compared with 9% NHW (P = .005). CONCLUSION: Individuals of Hispanic ethnicity were significantly more likely to harbor a VUS compared with NHW. The extended reach into our regional communities revealed a gap in the ability to accurately interpret genomic variation with implications for advising patients on screening, prevention, and management strategies. A higher percentage of VUS also emphasizes the challenge of continued follow-up amid existing barriers that led to disparities in access. As understanding of the variants develops, hopefully gaps in knowledge of the genomic landscape will be lessened with increased clarity to provide accurate cancer risk assessment and recommendations for implementing prevention initiatives.

Candidate gene association analysis of acute lymphoblastic leukemia identifies new susceptibility locus at 11p15 (LMO1).

To determine the contribution of susceptibility loci in explaining the genetic basis of acute lymphoblastic leukemia (ALL), we genotyped 29 high-potential candidate genes with 672 tagged single-nucleotide polymorphisms (SNPs) in a sample (163 cases and 251 healthy controls) of Caucasian children. Fifty SNPs in 15 genes were significantly associated with ALL risk at the P < 0.05 level. After correction for multiple testing, rs442264 within the LIM domain only 1 (LMO1) gene at 11p15 remained significant [odds ratio (OR) = 1.90, P = 3 × 10(-5)]. In addition, a major haplotype within LMO1 comprising 14 SNPs with individual risk associations was found to significantly increase ALL risk (OR = 1.79, P = 0.0006). A stratified analysis on subtype indicated that risk associations of LMO1 variants are significant in children with precursor B-cell leukemia. These data show that genetic variants within LMO1 are associated with ALL and identify this gene as a strong candidate for precursor B-cell leukemogenesis.

Germline mutations in PALB2 in African-American breast cancer cases.

Breast cancer incidence is lower in African Americans than in Caucasian Americans. However, African-American women have higher breast cancer mortality rates and tend to be diagnosed with earlier-onset disease. Identifying factors correlated to the racial/ethnic variation in the epidemiology of breast cancer may provide better understanding of the more aggressive disease at diagnosis. Truncating germline mutations in PALB2 have been identified in approximately 1% of early-onset and/or familial breast cancer cases. To date, PALB2 mutation testing has not been performed in African-American breast cancer cases. We screened for germline mutations in PALB2 in 139 African-American breast cases by denaturing high-performance liquid chromatography and direct sequencing. Twelve variants were identified in these cases and none caused truncation of the protein. Three missense variants, including two rare variants (P8L and T300I) and one common variant (P210L), were predicted to be pathogenic, and were located in a coiled-coil domain of PALB2 required for RAD51- and BRCA1-binding. We investigated and found no significant association between the P210L variant and breast cancer risk in a small case-control study of African-American women. This study adds to the literature that PALB2 mutations, although rare, appear to play a role in breast cancer in all populations investigated to date.