Parental Understanding of Their Child's Germline Genomic Testing: Intent of Disclosure to Their Child and Family.

Genomic testing is becoming increasingly common in the care of pediatric patients with cancer. Parental understanding of germline results and their intent and timing of results disclosure to their child and family may have significant implications on the family unit. The purpose of this study was to examine parental understanding of germline genomic results and plans for disclosure to their child and other relatives. Semi-structured interviews were conducted with 64 parents of children with cancer, approximately eight weeks after parents had received their child's results. Parents of children with negative results (n = 20), positive results (n = 15), or variants of uncertain significance (n = 29), were interviewed. Fifty-three parents (83%) correctly identified their child's results as negative, uncertain, or positive. Most parents had disclosed results to family members; however, only 11 parents (17%) acknowledged discussing results with their child. Most parents delayed disclosure due to the young age of their child at the time of testing. In summary, most parents appropriately described their child's germline genomic results, yet few discussed the results with their child due to age. Families should be followed with supportive counseling to assist parents in the timing and content of result disclosure to their children.

Parent Quality of Life After Disclosure of Pediatric Oncology Germline Sequencing Results.

PURPOSE: To characterize parents' quality of life (QoL) after germline genomic sequencing for their children with cancer. METHODS: Participants were n = 104 parents of children with cancer enrolled in a prospective study of clinical tumor and germline genomic sequencing. Parents completed surveys at study consent (T0), before disclosure of their child's germline results (T1), and again ≥5 weeks after results disclosure (T2). Bivariate associations with QoL were examined, followed by a multivariable regression model predicting parents' psychological distress. RESULTS: At T2, parental distress significantly differed by their children's germline result type (positive, uncertain, negative; P = .038), parent relationship status (P = .04), predisclosure genetics knowledge (P = .006), and predisclosure worry about sequencing (P < .001). Specifically, parents of children with positive (ie, pathogenic or likely pathogenic) results experienced greater distress than those of children with negative results (P = .029), as did parents who were single, more knowledgeable about genetics, and with greater worry. In the adjusted regression model, a positive germline result remained significantly associated with parents' lower QoL at T2 follow-up (F [4,92] = 9.95; P < .001; R2 = .30; ß = .19; P = .031). CONCLUSION: Germline genomic sequencing for children with cancer is associated with distress among parents when revealing an underlying cancer predisposition among their affected children. Genetic education and counseling before and after germline sequencing may help attenuate this impact on QoL by addressing parents' concerns about test results and their health implications. Assessing parents' worry early in the testing process may also aid in identifying those most likely in need of psychosocial support.

Pathogenic Variants in Adult-Onset Cancer Predisposition Genes in Pediatric Cancer: Prevalence and Impact on Tumor Molecular Features and Clinical Management.

PURPOSE: Clinical genomic sequencing of pediatric tumors is increasingly uncovering pathogenic variants in adult-onset cancer predisposition genes (aoCPG). Nevertheless, it remains poorly understood how often aoCPG variants are of germline origin and whether they influence tumor molecular profiles and/or clinical care. In this study, we examined the prevalence, spectrum, and impacts of aoCPG variants on tumor genomic features and patient management at our institution. EXPERIMENTAL DESIGN: This is a retrospective study of 1,018 children with cancer who underwent clinical genomic sequencing of their tumors. Tumor genomic data were queried for pathogenic variants affecting 24 preselected aoCPGs. Available tumor whole-genome sequencing (WGS) data were evaluated for second hit mutations, loss of heterozygosity (LOH), DNA mutational signatures, and homologous recombination deficiency (HRD). Patients whose tumors harbored one or more pathogenic aoCPG variants underwent subsequent germline testing based on hereditary cancer evaluation and family or provider preference. RESULTS: Thirty-three patients (3%) had tumors harboring pathogenic variants affecting one or more aoCPGs. Among 21 tumors with sufficient WGS sequencing data, six (29%) harbored a second hit or LOH affecting the remaining aoCPG allele with four of these six tumors (67%) also exhibiting a DNA mutational signature consistent with the altered aoCPG. Two additional tumors demonstrated HRD, of uncertain relation to the identified aoCPG variant. Twenty-one of 26 patients (81%) completing germline testing were positive for the aoCPG variant in the germline. All germline-positive patients were counseled regarding future cancer risks, surveillance, and risk-reducing measures. No patients had immediate cancer therapy changed due to aoCPG data. CONCLUSIONS: AoCPG variants are rare in pediatric tumors; however, many originate in the germline. Almost one third of tumor aoCPG variants examined exhibited a second hit and/or conferred an abnormal DNA mutational profile suggesting a role in tumor formation. aoCPG information aids in cancer risk prediction but is not commonly used to alter the treatment of pediatric cancers.

Managing Pandora's Box: Familial Expectations around the Return of (Future) Germline Results.

BACKGROUND: Pediatric oncology patients are increasingly being offered germline testing to diagnose underlying cancer predispositions. Meanwhile, as understanding of variant pathogenicity evolves, planned reanalysis of genomic results has been suggested. Little is known regarding the types of genomic information that parents and their adolescent children with cancer prefer to receive at the time of testing or their expectations around the future return of genomic results. METHODS: Parents and adolescent children with cancer eligible for genomic testing for cancer predisposition were surveyed regarding their attitudes and expectations for receiving current and future germline results (ClinicalTrials.gov Identifier: NCT02530658). RESULTS: All parents (100%) desired to learn about results for treatable or preventable conditions, with 92.4% wanting results even when there is no treatment or prevention. Parents expressed less interest in receiving uncertain results for themselves (88.3%) than for their children (95.3%). Most parents (95.9%) and adolescents (87.9%) believed that providers have a responsibility to share new or updated germline results indefinitely or at any point during follow-up care. Fewer parents (67.5%) indicated that they would want results if their child was deceased: 10.3% would not want to be contacted, 19.3% were uncertain. CONCLUSIONS: Expectations for return of new or updated genomic results are high among pediatric oncology families, although up to one third of parents have reservations about receiving such information in the event of their child's death. These results underscore the importance of high-quality pre-and post-test counseling, conducted by individuals trained in consenting around genomic testing to elicit family preferences and align expectations around the return of germline results.

Genomes for Kids: The Scope of Pathogenic Mutations in Pediatric Cancer Revealed by Comprehensive DNA and RNA Sequencing.

Genomic studies of pediatric cancer have primarily focused on specific tumor types or high-risk disease. Here, we used a three-platform sequencing approach, including whole-genome sequencing (WGS), whole-exome sequencing (WES), and RNA sequencing (RNA-seq), to examine tumor and germline genomes from 309 prospectively identified children with newly diagnosed (85%) or relapsed/refractory (15%) cancers, unselected for tumor type. Eighty-six percent of patients harbored diagnostic (53%), prognostic (57%), therapeutically relevant (25%), and/or cancer-predisposing (18%) variants. Inclusion of WGS enabled detection of activating gene fusions and enhancer hijacks (36% and 8% of tumors, respectively), small intragenic deletions (15% of tumors), and mutational signatures revealing of pathogenic variant effects. Evaluation of paired tumor-normal data revealed relevance to tumor development for 55% of pathogenic germline variants. This study demonstrates the power of a three-platform approach that incorporates WGS to interrogate and interpret the full range of genomic variants across newly diagnosed as well as relapsed/refractory pediatric cancers. SIGNIFICANCE: Pediatric cancers are driven by diverse genomic lesions, and sequencing has proven useful in evaluating high-risk and relapsed/refractory cases. We show that combined WGS, WES, and RNA-seq of tumor and paired normal tissues enables identification and characterization of genetic drivers across the full spectrum of pediatric cancers. This article is highlighted in the In This Issue feature, p. 2945.

Knowledge Is Power: Benefits, Risks, Hopes, and Decision-Making Reported by Parents Consenting to Next-Generation Sequencing for Children and Adolescents with Cancer.

OBJECTIVES: To qualitatively describe parent perspectives of next-generation genomic sequencing (NGS) for their children with cancer, including perceived benefits, risks, hopes/expectations, and decision-making process when consenting or not consenting to NGS and prior to result disclosure. DATA SOURCES: Qualitative interviews were used. CONCLUSION: Altruism is an important factor in parents consenting to NGS testing, as well as making sense of their child's cancer and legacy building. Parents described realistic hopes and expectations associated with NGS participation. Although parents endorsed the likelihood of no medical benefit, those consenting to NGS felt there was no reason not to participate. Parents declining participation expressed avoidance of worry and parent guilt if a germline variant were to be disclosed. IMPLICATIONS FOR NURSING PRACTICE: As NGS evolves into a component of the routine diagnostic workup for pediatric cancer patients, genetic nurses play a role in conducting informed consent conversations and ensuring that patients and families have realistic hopes and expectations associated with NGS.

Factors Associated with Declining to Participate in a Pediatric Oncology Next Generation Sequencing Study.

PURPOSE: For the advances of pediatric oncology next generation sequencing (NGS) research to equitably benefit all children, a diverse and representative sample of participants is needed. However, little is known about demographic and clinical characteristics that differentiate families who decline enrollment in pediatric oncology NGS research. METHODS: Demographic and clinical data were retrospectively extracted for 363 pediatric oncology patients (0-21 years) approached for enrollment on Genomes for Kids (G4K), a study examining the feasibility of comprehensive clinical genomic analysis of tumors and paired normal samples. Demographic and clinical factors that significantly differentiated which families declined were subsequently compared to enrollment in Clinical Implementation of Pharmacogenetics (PG4KDS) for 348 families, a pharmacogenomics study with more explicit therapeutic benefit examining genes affecting drug responses and metabolism. RESULTS: Fifty-three (14.6%) families declined enrollment in G4K. Race/ethnicity was the only variable that significantly differentiated study refusal using multivariate logistic regression, with families of black children more likely to decline enrollment compared to families of non-Hispanic or Hispanic white children. Reasons for declining G4K were generally consistent with other pediatric genomics research, with feeling overwhelmed and insurance discrimination fears most frequently cited. Families of black children were also more likely to decline enrollment in PG4KDS. Thirteen (3.7%) of the 348 families approached for both studies declined PG4KDS. CONCLUSION: Race/ethnicity differentiated study declination across two different pediatric oncology genomics studies, suggesting enrollment disparities in the context of pediatric oncology genomics research. Genomics research participant samples that do not fully represent racial and ethnic minorities risk further exacerbating health disparities. Additional work is needed to understand the nuances of parental decision making in genomic research and facilitate enrollment of diverse patient populations.

Enrichment of heterozygous germline RECQL4 loss-of-function variants in pediatric osteosarcoma.

Patients harboring germline pathogenic biallelic variants in genes involved in the recognition and repair of DNA damage are known to have a substantially increased cancer risk. Emerging evidence suggests that individuals harboring heterozygous variants in these same genes may also be at heightened, albeit lesser, risk for cancer. Herein, we sought to determine whether heterozygous variants in RECQL4, the gene encoding an essential DNA helicase that is defective in children with the autosomal recessive cancer-predisposing condition Rothmund-Thomson syndrome (RTS), are associated with increased risk for childhood cancer. To address this question, we interrogated germline sequence data from 4435 pediatric cancer patients at St. Jude Children's Research Hospital and 1127 from the National Cancer Institute Therapeutically Applicable Research to Generate Effective Treatment (TARGET) database and identified 24 (0.43%) who harbored loss-of-function (LOF) RECQL4 variants, including five of 249 (2.0%) with osteosarcoma (OS). These RECQL4 variants were significantly overrepresented in children with OS, the cancer most frequently observed in patients with RTS, as compared to 134,187 noncancer controls in the Genome Aggregation Database (gnomAD v2.1; P = 0.00087, odds ratio [OR] = 7.1, 95% CI, 2.9-17). Nine of the 24 (38%) individuals possessed the same c.1573delT (p.Cys525Alafs) variant located in the highly conserved DNA helicase domain, suggesting that disruption of this domain is central to oncogenesis. Altogether these data expand our understanding of the genetic factors predisposing to childhood cancer and reveal a novel association between heterozygous RECQL4 LOF variants and development of pediatric OS.

Speaking genomics to parents offered germline testing for cancer predisposition: Use of a 2-visit consent model.

BACKGROUND: Patients with cancer are increasingly offered genomic sequencing, including germline testing for cancer predisposition or other disorders. Such testing is unfamiliar to patients and families, and clear communication is needed to introduce genomic concepts and convey risk and benefit information. METHODS: Parents of children with cancer were offered the opportunity to have their children's tumor and germline examined with clinical genomic sequencing. Families were introduced to the study with a 2-visit informed consent model. Baseline genetic knowledge and self-reported literacy/numeracy were collected before a study introduction visit, during which basic concepts related to genomic sequencing were discussed. Information was reinforced during a second visit, during which informed consent was obtained and a posttest was administered. RESULTS: As reflected by the percentage of correct answers on the pretest and posttest assessments, this model increased genetic knowledge by 11.1% (from 77.8% to 88.9%; P < .0001) in 121 parents participating in both the study introduction and consent visits. The percentage of parents correctly identifying the meaning of somatic and germline mutations increased significantly (from 18% to 59% [somatic] and from 31% to 64% [germline]; P < .0001). Nevertheless, these concepts remained unfamiliar to one-third of the parents. No relation was identified between the change in the overall percentage of correct answers and self-reported literacy, numeracy, or demographics. CONCLUSIONS: The use of a 2-visit communication model improved knowledge of concepts relevant to genomic sequencing, particularly differences between somatic and germline testing; however, these areas remained confusing to many participants, and reinforcement may be necessary to achieve complete understanding.

Efficient construction of producer cell lines for a SIN lentiviral vector for SCID-X1 gene therapy by concatemeric array transfection.

Retroviral vectors containing internal promoters, chromatin insulators, and self-inactivating (SIN) long terminal repeats (LTRs) may have significantly reduced genotoxicity relative to the conventional retroviral vectors used in recent, otherwise successful clinical trials. Large-scale production of such vectors is problematic, however, as the introduction of SIN vectors into packaging cells cannot be accomplished with the traditional method of viral transduction. We have derived a set of packaging cell lines for HIV-based lentiviral vectors and developed a novel concatemeric array transfection technique for the introduction of SIN vector genomes devoid of enhancer and promoter sequences in the LTR. We used this method to derive a producer cell clone for a SIN lentiviral vector expressing green fluorescent protein, which when grown in a bioreactor generated more than 20 L of supernatant with titers above 10(7) transducing units (TU) per milliliter. Further refinement of our technique enabled the rapid generation of whole populations of stably transformed cells that produced similar titers. Finally, we describe the construction of an insulated, SIN lentiviral vector encoding the human interleukin 2 receptor common gamma chain (IL2RG) gene and the efficient derivation of cloned producer cells that generate supernatants with titers greater than 5 x 10(7) TU/mL and that are suitable for use in a clinical trial for X-linked severe combined immunodeficiency (SCID-X1).

Intravascular administration of tumor tropic neural progenitor cells permits targeted delivery of interferon-beta and restricts tumor growth in a murine model of disseminated neuroblastoma.

BACKGROUND: Interferon-beta (IFN-beta) has potent antitumor activity; however, systemic toxicity has limited its clinical use. We investigated the potential of targeted delivery using tumor-tropic neural progenitor cells (NPCs) transduced to express human IFN-beta (hIFN-beta). METHODS: Disseminated neuroblastoma was established in SCID mice by tail vein injection of tumor cells. Fourteen days after tumor cell inoculation, systemic disease was confirmed with bioluminescence imaging (BLI). Mice were then treated by intravenous injection of human F3.C1 NPCs that had been transduced with a replication deficient adenovirus to overexpress hIFN-beta (F3-IFN-beta). Two injections were given: the first at 14 days and the second at 28 days following tumor cell injection. Control mice received NPCs transduced with empty vector adenovirus at the same time points. Progression of disease was monitored using BLI. At sacrifice, organ weights and histology further evaluated tumor burden. RESULTS: After initiation of therapy, BLI demonstrated a significant decrease in the rate of disease progression in mice receiving F3-IFN-beta. At necropsy, control mice had bulky tumor replacing the liver and kidneys, as well as extensive retroperitoneal and mediastinal adenopathy. Impressively, these sites within mice receiving F3-IFN-beta therapy appeared grossly normal with the exception of small nodules within the kidneys of some of the F3-IFN-beta-treated mice. The accumulation of F3.C1 cells within sites of tumor growth was confirmed by fluorescence imaging. Importantly, systemic levels of hIFN-beta in the treated mice remained below detectable levels. CONCLUSIONS: These data indicate that in this model of disseminated neuroblastoma, the tumor-tropic property of F3.C1 NPCs was exploited to target delivery of IFN-beta to disseminated tissue foci, resulting in significant tumor growth delay. The described novel approach for effective IFN-beta therapy may circumvent limitations associated with the systemic toxicity of IFN-beta.