Childhood tumours with a high probability of being part of a tumour predisposition syndrome; reason for referral for genetic consultation

Cancer Predisposition Syndromes in Children: Who, How, and When Should Genetic Studies Be Considered?

Early detection of cancer predisposition syndromes (CPS) is crucial to determine optimal treatments and follow-up, and to provide appropriate genetic counseling. This study outlines an approach in a pediatric oncology unit, where 50 randomly selected patients underwent clinical assessment, leading to 44 eligible for genetic testing. We identified 2 pathogenic or likely pathogenic variants in genes associated with CPS and 6 variants of uncertain significance (VUS) potentially associated with cancer development. We emphasize the importance of a thorough and accurate collection of family history and physical examination data and the full coordination between pediatric oncologists and geneticists.

Genetic predisposition to childhood cancer

The etiology of childhood cancer remains largely unknown. Recent evidence suggests that genetic factors play a substantial role in pediatric tumorigenesis. Unlike adult cancers, pediatric cancers typically have a higher prevalence of germline pathogenic variants in cancer predisposition genes. Inherited cancer predisposition syndromes account for approximately 10% of all childhood cancers. Over the years, the diagnosis of cancer predisposition syndromes was based on clinical suspicion prompting referral to a specialized geneticist. However, advances in molecular technologies have led to a shift toward a "genotype-first" approach. Identification of genetic variants related to cancer predisposition enables tailored treatment, improves clinical outcome, optimizes surveillance, and facilitates genetic counseling of the affected child and the family.

Hereditary Conditions Associated with Elevated Cancer Risk in Childhood

Received January, 31, 2023 Revised March, 16, 2023 Accepted March, 18, 2023 Widespread use of the next-generation sequencing (NGS) technologies revealed that a significant percentage of tumors in children develop as a part of monogenic hereditary diseases. Predisposition to the development of pediatric neoplasms is characteristic of a wide range of conditions including hereditary tumor syndromes, primary immunodeficiencies, RASopathies, and phakomatoses. The mechanisms of tumor molecular pathogenesis are diverse and include disturbances in signaling cascades, defects in DNA repair, chromatin remodeling, and microRNA processing. Timely diagnosis of tumor-associated syndromes is important for the proper choice of cancer treatment, genetic counseling of families, and development of the surveillance programs. The review describes the spectrum of neoplasms characteristic of the most common syndromes and molecular pathogenesis of these diseases.

SMARCE1-related meningiomas: A clear example of cancer predisposing syndrome

We report the case of a 16-year-old girl presenting with spinal clear-cell multiple meningiomas (CCMs). In view of this presentation, we sequenced a bioinformatic panel of genes associated with susceptibility to meningioma, identifying a germline heterozygous variant inSMARCE1. Somatic DNA investigations in the CCM demonstrated the deletion of the wild-type allele (loss of heterozygosity, LOH), supporting the causative role of this variant. Family segregation study detected the SMARCE1 variant in the asymptomatic father and in the asymptomatic sister who, nevertheless, presents 2 spinal lesions. Germline heterozygous loss-of-function (LoF) variants in SMARCE1, encoding a protein of the chromatin-remodeling complex SWI/SNF, have been described in few familial cases of susceptibility to meningioma, in particular the CCM subtype. Our case confirms the role of NGS in investigating predisposing genes for meningiomas (multiple or recurrent), with specific regard to SMARCE1 in case of pediatric CCM. In addition to the age of onset, the presence of familial clustering or the coexistence of multiple synchronous meningiomas also supports the role of a genetic predisposition that deserves a molecular assessment. Additionally, given the incomplete penetrance, it is of great importance to follow a specific screening or follow-up program for symptomatic and asymptomatic carriers of pathogenic variants in SMARCE1.

The genetic era of childhood cancer: Identification of high-risk patients and germline sequencing approaches

Childhood cancer is a leading cause of death by disease in children ages 5-14, for which there are no preventive strategies. Due to early-age of diagnosis and short period of exposure to environmental factors, increasing evidence suggests childhood cancer could have strong association with germline alterations in predisposition cancer genes but, their frequency and distribution are largely unknown. Several efforts have been made to develop tools to identify children with increased risk of cancer who may benefit from genetic testing but their validation and application on a large scale is necessary. Research on genetic bases of childhood cancer is ongoing, in which several approaches for the identification of genetic variants related to cancer predisposition have been used. In this paper, we discuss the updated efforts, strategies, molecular mechanisms and clinical implications for germline predisposition gene alterations and the characterization of risk variants in childhood cancer.

Considerations in Methods and Timing for Delivery of Genetic Counseling Information to Pediatric Oncology Patients and Families

Many pediatric oncology patients and their families may benefit from genetic counseling and testing; however, identifying the best timing and delivery method for these referrals is sometimes a challenge. The goal of this study was to understand how and when caregivers prefer to receive information about genetic counseling and testing. A total of 56 surveys completed by caregivers at The Johns Hopkins Hospital Pediatric Oncology unit in Baltimore, Maryland were analyzed. A sizeable subset of respondents was interested in receiving information about the availability of genetic counseling from an oncology doctor or nurse, but not a genetic counselor (n=13/55, 24%). Most respondents preferred to be informed about genetic services at diagnosis (n=28/54, 52%) or within 1 to 2 months of diagnosis (n=14/54, 26%). In conclusion, patients and their families may benefit from prompt and early recognition of the risk of cancer predisposition syndromes, preferably within the first 2 months following diagnosis. Oncology professionals are an important source of information, and can introduce the availability of genetic counseling services and motivate families to undergo genetic testing, though alternative communication methods such as brochures may also be useful.

Maternal Thyroid Disease and the Risk of Childhood Cancer in the Offspring

Maternal thyroid disease, especially hypothyroidism, affects pregnancy and its outcome. In-utero exposure to autoimmune thyroid disease has been reported to associate with childhood ALL in the offspring. We evaluated the risk of childhood cancer in the offspring following exposure to maternal thyroid disease in a case-control setting using registry data. All patients with their first cancer diagnosis below the age of 20 years were identified from the Finnish Cancer Registry (n = 2037) and matched for sex and birth year at a 1:5 ratio to population controls identified from the Medical Birth Registry (n = 10,185). We collected national information on maternal thyroid disease from the Medical Birth Registry, Care Register for Health Care, Register for Reimbursed Drug Purchases and Register of Special Reimbursements. We used conditional logistic regression to analyze childhood cancer risk in the offspring. The adjusted OR for any childhood cancer was 1.41 (95%, CI 1.00-2.00) comparing the offspring of mothers with hypothyroidism and those with normal thyroid function. The risk of lymphomas was increased (adjusted OR for maternal hypothyroidism 3.66, 95%, CI 1.29-10.38). The results remained stable when mothers with cancer history were excluded from the analyses. Maternal hypothyroidism appears to be associated with an increased risk for childhood lymphoma in the offspring. The association exists even after excluding possible familial cancers.

Improving Detection of Cancer Predisposition Syndromes in Pediatric Oncology

Implementation and adherence to consensus statement criteria for referral of pediatric cancer patients for genetic evaluation are critical to identify the 5% to 10% with a genetic cancer predisposition syndrome. The authors implemented a Plan-Do-Study-Act quality improvement initiative aimed at increasing referrals of at-risk patients. Retrospective chart review was followed by educational intervention-with impact assessed over a 9-month prospective chart review. Referral rate improved >2-fold and there was an improvement in documented oncologic history to at least a third-degree relative. The integration of quality improvement can be an effective tool to improve the referral of patients with an elevated risk for a cancer predisposition syndrome.

Eye Tumors in Childhood as First Sign of Tumor Predisposition Syndromes: Insights from an Observational Study Conducted in Germany and Austria

Simple Summary

Eye tumors in children are very rare. In Europe, these eye tumors are nearly always diagnosed early and cure rates are high. However, eye tumors in childhood often occur as the first sign of a genetic tumor predisposition syndrome. This study collected data of children with malignant eye tumors diagnosed in five years in Germany and Austria to learn about the association of eye tumors in childhood with tumor predisposition syndrome. The study recruited 300 children with malignant eye tumors in childhood. In the here-presented cohort, more than 40% of eye tumors were associated with rare tumor predisposition syndromes. For this reason, all children with eye tumors and their families should receive genetic counseling for a tumor predisposition syndrome. Children with a genetic predisposition to cancer should receive a tailored surveillance, including detailed history, physical examination and, if indicated, imaging to screen for other cancers later in life.

Abstract

Retinoblastoma and other eye tumors in childhood are rare diseases. Many eye tumors are the first signs of a genetic tumor predisposition syndrome and the affected children carry a higher risk of developing other cancers later in life. Clinical and genetic data of all children with eye tumors diagnosed between 2013–2018 in Germany and Austria were collected in a multicenter prospective observational study. In five years, 300 children were recruited into the study: 287 with retinoblastoma, 7 uveal melanoma, 3 ciliary body medulloepithelioma, 2 retinal astrocytoma, 1 meningioma of the optic nerve extending into the eye. Heritable retinoblastoma was diagnosed in 44% of children with retinoblastoma. One child with meningioma of the optic nerve extending into the eye was diagnosed with neurofibromatosis 2. No pathogenic constitutional variant in DICER1 was detected in a child with medulloepithelioma while two children did not receive genetic analysis. Because of the known association with tumor predisposition syndromes, genetic counseling should be offered to all children with eye tumors. Children with a genetic predisposition to cancer should receive a tailored surveillance including detailed history, physical examinations and, if indicated, imaging to screen for other cancer. Early detection of cancers may reduce mortality.

Clinical value of a screening tool for tumor predisposition syndromes in childhood cancer patients (TuPS): a prospective, observational, multi-center study

Recognizing a tumor predisposition syndrome (TPS) in a child with cancer is of clinical relevance. Earlier we developed a screening tool to increase diagnostic accuracy and clinical efficiency of identifying TPSs in children with cancer. Here we report on the value of this tool in clinical practice. TuPS is a prospective, observational, multi-center study including children newly diagnosed with cancer from 2016 to 2019 in the Netherlands. Children in whom a TPS had been diagnosed before the cancer diagnosis were excluded. The screening tool consists of a checklist, 2D and 3D photographic series and digital assessment of these by a clinical geneticist. If a TPS was suspected, the patient was assessed positive and referred for routine genetic consultation. Primary aim was to assess the clinical value of this new screening tool. Of the 363 included patients, 57% (208/363) were assessed positive. In 15% of patients (32/208), the 2D photographic series with (n = 12) or without (n = 20) 3D photographs were decisive in the positive assessment. In 2% (4/208) of positive assessed patients, a TPS was diagnosed, and in an additional 2% (4/208) a germline variant of uncertain significance was found. Thirty-five negatively assessed patients were evaluated through routine genetic consultation as controls, in none a TPS was detected. Using the screening tool, 57% of the patients were assessed as suspected for having a TPS. No false negative results were identified in the negative control group in the clinical care setting. The observed prevalence of TPS was lower than expected, due to selection bias in the cohort.

Proportion of children with cancer that have an indication for genetic counseling and testing based on the cancer type irrespective of other features

In children with cancer, specific clinical features such as physical anomalies, occurrence of cancer in young relatives, specific cancer histologies, and unique mutation/methylation signatures may indicate the presence of an underlying cancer predisposition syndrome (CPS). The proportion of children with a cancer type suggesting a CPS among all children with cancer is unknown. To determine the proportion of children with cancer types suggesting an underlying CPS among children with cancer. We evaluated the number of children with cancer types strongly associated with CPS diagnosed in Germany between 2007 and 2016. Data were obtained from various sources including two national pediatric pathology reference laboratories for brain and solid tumors, respectively, various childhood cancer trial offices as well as the German Childhood Cancer Registry. Among 21,127 children diagnosed with cancer between 2007 and 2016, 2554 (12.1%) had a cancer type strongly associated with a CPS. The most common diagnoses were myelodysplastic syndrome and juvenile myelomonocytic leukemia, retinoblastoma, malignant peripheral nerve sheath tumor, infantile myofibromatosis, medulloblastoma^SHH, rhabdoid tumor as well as atypical teratoid/rhabdoid tumor. Based on cancer type only, 12.1% of all children with cancer have an indication for a genetic evaluation. Pediatric oncology patients require access to genetic counselling and testing.

Pediatric Lymphoma and Solid Tumors Associated With Cancer Susceptibility Syndromes

The aim of this study was to determine cancer susceptibility syndromes (CSSs) in children with lymphoma and solid tumors and to evaluate their effects on overall survival rates. Between 2006 and 2019, the oncologic charts of 672 patients who were followed-up with a diagnosis of lymphoma and solid tumor in our clinic were retrospectively reviewed. CSSs were detected in 42 children (6.25%). The most common CSS was DNA damage repair defects/genetic instability (in 18 of 42 patients with CSSs, 42.8%). In the patients with CSSs, 48 different cancers developed. The most common types of cancer were lymphoma (n: 10, 21%) and high-grade glial tumor (n: 9, 19%). The lymphoma subgroups were very rare childhood lymphomas, such as gray zone lymphoma and marginal zone lymphoma. The overall survival rates for patients with DNA damage repair defects/genetic instability; with CSSs other than DNA damage repair defects/patients with genetic instability syndrome; and without any CSS, were 9.7%, 65.1%, and 68.7%, respectively. The overall survival rate for patients with DNA damage repair defects/patients with genetic instability syndrome was lower than both patients with CSSs other than DNA damage repair defects/genetic instability syndrome (P=0.002) and those without any CSS (P<0.0001). CSSs should be kept in mind in children with cafe au lait spots; syndromic features; a family history of cancer, especially in siblings; and rare childhood cancers.

Precision oncology: A primer for pediatric surgeons from the APSA cancer committee

Although most children with cancer can be cured of their disease, a subset of patients with adverse tumor types or biological features, and those with relapsed or refractory disease have significantly worse prognosis. Furthermore, current cytotoxic therapy is associated with significant late effects. Precision oncology, using molecular therapeutics targeted against unique genetic features of the patient's tumor, offers the potential to transform the multimodal therapy for these patients. Potentiated by advances in sequencing technology and molecular therapeutic development, and accelerated by large-scale multi-institutional basket trials, the field of pediatric precision oncology has entered the mainstream. These novel therapeutics have important implications for surgical decision making, as well as pre- and postoperative care. This review summarizes the current state of precision medicine in pediatric oncology including the active North American and European precision oncology clinical trials. LEVEL OF EVIDENCE: Treatment study Level V.

Pediatric Somatic Tumor Sequencing Identifies Underlying Cancer Predisposition

PURPOSE

The diagnosis of cancer predisposition in pediatric patients with cancer is vital for treatment decisions, surveillance, and management of at-risk family members. Somatic tumor testing can identify potential underlying constitutional variants that confer increased cancer risk. Here, we report the characteristics of constitutional variants identified through tumor testing.

MATERIALS AND METHODS

Data were abstracted from medical record review of 1,023 patients who received inhouse somatic tumor testing over a 28-month period. Patients were identified for testing using referral criteria developed as a collaboration between genomic diagnostics, pathology, and oncology. Characteristics of patients who underwent constitutional testing, including family history and variant loss of heterozygosity, were tracked.

RESULTS

From 1,023 patients who underwent somatic tumor sequencing in a 28-month period, 210 variants were identified in 141 patients (13.8%) that were concerning for cancer predisposition syndromes requiring intervention. A total of 73 variants in 41 patients have undergone clinical confirmatory testing thus far. Of these, 26 variants were confirmed to be constitutionally present (35.6%). Among patients tested, 23 (56.1%) of 41 total patients were diagnosed with a cancer predisposition syndrome.

CONCLUSION

Our data demonstrate that more than one third of variants in tumor somatic sequencing that were concerning for underlying cancer predisposition were constitutionally confirmed. Overall, somatic tumor testing identified potential cancer predisposition syndromes in pediatric patients, and some would not have been identified on the basis of clinical history alone.

Genetic Predisposition to Childhood Cancer in the Genomic Era

Developments over the past five years have significantly advanced our ability to use genome-scale analyses—including high-density genotyping, transcriptome sequencing, exome sequencing, and genome sequencing—to identify the genetic basis of childhood cancer. This article reviews several key results from an expanding number of genomic studies of pediatric cancer: ( a) Histopathologic subtypes of cancers can be associated with a high incidence of germline predisposition, ( b) neurodevelopmental disorders or highly penetrant cancer predisposition syndromes can result from specific patterns of variation in genes encoding the SMARC family of chromatin remodelers, ( c) genome-wide association studies with relatively small pediatric cancer cohorts have successfully identified single-nucleotide polymorphisms with large effect sizes and provided insight into population differences in cancer risk, and ( d) multiple exome or genome analyses of unselected childhood cancer cohorts have yielded a 7–10% incidence of pathogenic variants in cancer predisposition genes. This work supports the increasing use of genomic sequencing in the care of pediatric cancer patients and at-risk family members.

Clinical relevance of screening checklists for detecting cancer predisposition syndromes in Asian childhood tumours

Assessment of cancer predisposition syndromes (CPS) in childhood tumours is challenging to paediatric oncologists due to inconsistent recognizable clinical phenotypes and family histories, especially in cohorts with unknown prevalence of germline mutations. Screening checklists were developed to facilitate CPS detection in paediatric patients; however, their clinical value have yet been validated. Our study aims to assess the utility of clinical screening checklists validated by genetic sequencing in an Asian cohort of childhood tumours. We evaluated 102 patients under age 18 years recruited over a period of 31 months. Patient records were reviewed against two published checklists and germline mutations in 100 cancer-associated genes were profiled through a combination of whole-exome sequencing and multiplex ligation-dependent probe amplification on blood-derived genomic DNA. Pathogenic germline mutations were identified in ten (10%) patients across six known cancer predisposition genes: TP53, DICER1, NF1, FH, SDHD and VHL. Fifty-four (53%) patients screened positive on both checklists, including all ten pathogenic germline carriers. TP53 was most frequently mutated, affecting five children with adrenocortical carcinoma, sarcomas and diffuse astrocytoma. Disparity in prevalence of germline mutations across tumour types suggested variable genetic susceptibility and implied potential contribution of novel susceptibility genes. Only five (50%) children with pathogenic germline mutations had a family history of cancer. We conclude that CPS screening checklists are adequately sensitive to detect at-risk children and are relevant for clinical application. In addition, our study showed that 10% of Asian paediatric solid tumours have a heritable component, consistent with other populations.

The International Childhood Cancer Cohort Consortium (I4C): A research platform of prospective cohorts for studying the aetiology of childhood cancers

BACKGROUND

Childhood cancer is a rare but leading cause of morbidity and mortality. Established risk factors, accounting for <10% of incidence, have been identified primarily from case-control studies. However, recall, selection and other potential biases impact interpretations particularly, for modest associations. A consortium of pregnancy and birth cohorts (I4C) was established to utilise prospective, pre-diagnostic exposure assessments and biological samples.

METHODS

Eligibility criteria, follow-up methods and identification of paediatric cancer cases are described for cohorts currently participating or planning future participation. Also described are exposure assessments, harmonisation methods, biological samples potentially available for I4C research, the role of the I4C data and biospecimen coordinating centres and statistical approaches used in the pooled analyses.

RESULTS

Currently, six cohorts recruited over six decades (1950s-2000s) contribute data on 388 120 mother-child pairs. Nine new cohorts from seven countries are anticipated to contribute data on 627 500 additional projected mother-child pairs within 5 years. Harmonised data currently includes over 20 "core" variables, with notable variability in mother/child characteristics within and across cohorts, reflecting in part, secular changes in pregnancy and birth characteristics over the decades.

CONCLUSIONS

The I4C is the first cohort consortium to have published findings on paediatric cancer using harmonised variables across six pregnancy/birth cohorts. Projected increases in sample size, expanding sources of exposure data (eg, linkages to environmental and administrative databases), incorporation of biological measures to clarify exposures and underlying molecular mechanisms and forthcoming joint efforts to complement case-control studies offer the potential for breakthroughs in paediatric cancer aetiologic research.

Consequences of diagnosing a tumor predisposition syndrome in children with cancer: A literature review

Up to 8.5% of children with cancer have a genetic cause for their cancer: a tumor predisposition syndrome (TPS). Diagnosing a TPS is of great importance, as it may have major consequences for clinical care. Patients with TPSs require specific monitoring and management. We present an overview of the cancer-related and noncancer-related consequences for the 36 most common TPSs.