Screening for Wilms' tumor in children with high-risk congenital syndromes: considerations for an intervention trial

Cancer predisposition signaling in Beckwith-Wiedemann Syndrome drives Wilms tumor development

BACKGROUND

Wilms tumor (WT) exhibits structural and epigenetic changes at chromosome 11p15, which also cause Beckwith-Wiedemann Syndrome (BWS). Children diagnosed with BWS have increased risk for WT. The aim of this study is to identify the molecular signaling signatures in BWS driving these tumors.

METHODS

We performed whole exome sequencing, methylation array analysis, and gene expression analysis on BWS-WT samples. Our data were compared to publicly available nonBWS data. We categorized WT from BWS and nonBWS patients by assessment of 11p15 methylation status and defined 5 groups- control kidney, BWS-nontumor kidney, BWS-WT, normal-11p15 nonBWS-WT, altered-11p15 nonBWS-WT.

RESULTS

BWS-WT samples showed single nucleotide variants in BCORL1, ASXL1, ATM and AXL but absence of recurrent gene mutations associated with sporadic WT. We defined a narrow methylation range stratifying nonBWS-WT samples. BWS-WT and altered-11p15 nonBWS-WT showed enrichment of common and unique molecular signatures based on global differential methylation and gene expression analysis. CTNNB1 overexpression and broad range of interactions were seen in the BWS-WT interactome study.

CONCLUSION

While WT predisposition in BWS is well-established, as are 11p15 alterations in nonBWS-WT, this study focused on stratifying tumor genomics by 11p15 status. Further investigation of our findings may identify novel therapeutic targets in WT oncogenesis.

Tumor Screening in Beckwith-Wiedemann Syndrome: Parental Perspectives

Children with Beckwith-Wiedemann Syndrome (BWS) and Isolated Hemihypertrophy (IHH) are at an increased risk for developing tumors. Tumor screening in this population is currently being reassessed by several groups and the effect on patients and patient-families has been argued both as a reason to screen and not to screen. Parental perspectives on this topic have never been systematically addressed for the BWS population. Here, we conducted a parent-based survey to evaluate knowledge and attitudes toward tumor screening in patients affected by BWS/IHH. A total of 261 surveys were completed. Overall, parents reported that screening decreased their worry and did not feel that screening increased worry or created a burden. This effect was observed across various demographic variables and other factors examined. Almost all significant differences observed could be attributed to parental knowledge of tumor risk. Parents who correctly identified their child's tumor risk were more likely to agree with stratified screening recommendations according to BWS type and risk, and were less likely to feel worried if recommendations were changed. These results highlight the need to educate families about their child's genetic type and tumor risk in order to facilitate an informed decision about tumor screening.

Bilateral disease and new trends in Wilms tumour

Wilms tumour is a great therapeutic success story within paediatric oncology; its prognosis is excellent. Although mainly sporadic, occurring in otherwise well children, it occurs in a small number of genetically predisposed children. Thus regular surveillance imaging is performed in predisposed children in parts of the USA and Europe. The risks and benefits of surveillance are unclear, as the existing ad-hoc surveillance protocols are lacking in consistency of practice and equity of provision. We present guidelines for Wilms tumour surveillance based on a review of current practice and available evidence, outlined by a multidisciplinary working group in the UK. Wilms tumours are bilateral in 4-13% of affected children. Bilateral synchronous nephroblastomas are observed in 5% of affected children and are usually associated with the presence of nephrogenic rests, congenital malformations and predisposing syndromes. The major challenge in bilateral disease is to achieve a cure and at the same time to preserve sufficient functional renal tissue for normal growth and development. The association among Wilms tumour, nephrogenic rests and nephroblastomatosis makes detection and characterization of renal lesions with imaging extremely important. We discuss the relative strengths and weaknesses of the different modalities used for diagnosis and follow-up in bilateral renal disease. We also discuss newly emerging diagnostic imaging tests such as (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET). This technique, when fused with CT (PET-CT), allows accelerated metabolic activity to be accurately anatomically localised and so is potentially useful for staging, assessment of treatment response, and for surgical and radiotherapy planning. In addition, quantitative MRI techniques have been proved to be valuable in intracranial tumours, but no such role has been validated in abdominal disease. Diffusion-weighted imaging with calculation of ADC maps is feasible in abdominal tumours, and our own preliminary data suggest that tissue cellularity is an important determinant of ADC value, which might help in terms of early prediction of therapy response.

The challenges of Proteus syndrome: diagnosis and management

Proteus syndrome (PS) is a disorder of patchy or mosaic postnatal overgrowth of unknown etiology. The onset of overgrowth typically occurs in infancy and can involve any tissue of the body. Commonly involved tissues include connective tissue and bone, skin, central nervous system, the eye, but it apparently can affect any tissue. Diagnosing of PS is difficult and the diagnostic criteria are controversial. Our group advocates stringent diagnostic criteria to facilitate research and appropriate clinical care. The benefit of strict criteria is that they define a clinical group that is reasonably homogenous with respect to manifestations and prognosis. The overgrowth of PS is progressive and can be difficult to manage. The progressive overgrowth most commonly causes severe orthopaedic complications, but it can cause many other complications. One of the most common complications in patients with PS is deep venous thrombosis and pulmonary embolism, which can cause premature death. Effective management requires knowledge of the wide array of manifestations and complications of the disorder and a team approach that includes the geneticist, surgeons, and other specialists.

High-frequency ultrasound detection and follow-up of Wilms' tumor in the mouse

The goal of this study was to validate high-frequency (24 MHz) ultrasound imaging techniques for early detection and follow-up of renal tumors in a murine Wilms' tumor model (n = 26). For 11 mice, maximum tumor dimensions were estimated from images along three orthogonal axes for comparison with posteuthanasia caliper and histologic measurements. Tumor size in the 15 remaining mice was checked biweekly. The mice were then euthanized and histologic study assessed tumor position and nature. Tumors were detected in vivo between 7 to 14 days after injection of tumor-inducing cells. Tumor maximum cross-sectional area varied from 0.07 mm2 to 5.7 mm2 at the time of initial detection. The relative r.m.s. error between ultrasonic and histologic estimations of maximum cross-sectional area was estimated to be 19%. Results demonstrate feasibility of noninvasive ultrasound biomicroscopy early detection and characterization of renal tumor development for longitudinal monitoring of the same animal.

Inheritance pattern of Beckwith-Wiedemann syndrome is heterogeneous in 291 families with an affected proband

Beckwith-Wiedemann syndrome (BWS) is congenital disorder whose molecular etiology is related to genetic and epigenetic mutations on 11p15. The majority of cases of BWS are sporadic, but a substantial proportion are familial, with an unknown inheritance pattern, although autosomal dominant and sex-dependent inheritance have been proposed. We tested the hypothesis that in familial BWS, autosomal dominant inheritance is the primary mode of transmission underlying familial instances. Segregation analysis was performed in 291 families ascertained with an affected child. Individuals were considered to have BWS if they had two of five major features: macroglossia, macrosomia, hypoglycemia at birth, abdominal wall defect, and ear pits or creases. Models of inheritance were tested using pedigree analysis package (PAP) parameterized for a discrete trait. A total of 291 families of an affected proband were included in the study. The analysis was based on a revised general model that included a boundary solution. Sporadic and environmental models were rejected. Overall, the results suggested Mendelian inheritance but under recessive or additive mode of inheritance, which fit the data equally well rather than dominant inheritance. However, the presence of families in the cohort consistent with dominant and sex-dependent inheritance suggest familial BWS may be a heterogeneous group comprised of different inheritance patterns. Familial BWS does not appear to be consistent with autosomal dominant transmission, and is likely a complex mixture of different inheritance patterns.

Factors associated with preterm delivery in mothers of children with Beckwith-Wiedemann syndrome: a case cohort study from the BWS registry

Pregnancy that results in a child with Beckwith-Wiedemann syndrome (BWS) is associated with preterm delivery. Based on previous case series, we hypothesized that preterm delivery of a child with BWS was due to known risk factors for preterm delivery such as polyhydramnios and gestational hypertension. A case cohort study using the BWS Registry at Washington University School of Medicine was undertaken. Cases were pregnancies that resulted in the birth of a child with BWS, controls were pregnancies resulting in the birth of siblings without BWS. Univariate analyses of maternal complications and logistic regression to predict preterm delivery were used. Children with BWS (n = 304) were delivered preterm at a significantly higher rate than their siblings (n = 269) odds ratio 19.1 (95% CI 9.1-40.2). Polyhydramnios, gestational hypertension, and vaginal bleeding also occurred at high rates in the BWS group with odds ratios of 31.6 (95% CI 12.6-79.1), 2.4 (95% CI 1.4-4.1), and 3.9 (95% CI 2.3-6.4), respectively. In a multivariate logistic regression model within the BWS group, polyhydramnios, vaginal bleeding, and gestational hypertension were significant predictors of preterm delivery, odds ratios of 2.9 (95% CI 1.6-5.4), 2.6 (95% CI 1.3-5.0), and 5.3 (2.3-12.0), respectively. However, a significant proportion, 6.5% (18 of 277), of patients in the BWS group delivered preterm without known risk factors. Preterm delivery of a child with BWS is associated with an increased frequency of polyhydramnios, gestational hypertension, and vaginal bleeding in the mother. However, preterm delivery also occurs in the absence of these risk factors.

Survival of children with Wilms' tumour in Europe

A total 2535 cases of Wilms' tumours registered in children aged 0--14 years by 34 population-based cancer registries in 16 countries of Europe in 1978--1992 and followed-up until the end of 1994 were included in this EUROCARE study. Overall 5-year observed survival of all children diagnosed in 1985--1989 was 83%, 95% confidence interval (CI) 80--85. Relatively large differences were observed between the European countries, with significantly lower survival of patients registered in the formerly socialist countries, Estonia, Poland and Slovakia. Overall European survival was slightly lower in comparison with results reported from the USA and Australia, which demonstrate a potential for improvement. Over the study period, overall survival adjusted for age, sex and country has increased significantly. This favourable trend is attributed primarily to improvements in treatment, particularly to the introduction of new chemotherapeutic agents.

Simpson Golabi Behmel syndrome: progress toward understanding the molecular basis for overgrowth, malformation, and cancer predisposition

Simpson Golabi Behmel syndrome (SGBS) is a complex congenital overgrowth syndrome with features that include macroglossia, macrosomia, and renal and skeletal abnormalities as well as an increased risk of embryonal cancers. Most cases of SGBS appear to arise as a result of either deletions or point mutations within the glypican-3 (GPC3) gene at Xq26, one member of a multigene family encoding for at least six distinct glycosylphophatidylinositol-linked cell surface heparan sulfate proteoglycans. As a class of molecules, heparan sulfate proteoglycans have been found to play essential roles in development by modulating cellular responses to growth factors and morphogens. Specifically, mutations in both the murine GPC3 gene and the Drosophila glypican, dally, have been found to modify cellular responses to bone morphogenetic proteins, providing important clues to the molecular basis of SGBS in humans. Despite these advances, there remains a paucity of information about the natural history of SGBS and optimal medical management strategies, and whether select mutations influence the SGBS phenotype and risk of cancer. To this end, an International SGBS Registry has been created and is being maintained to improve the clinical care and understanding of the pathogenesis of SGBS. Using an integrated approach employing epidemiology, molecular genetic characterization of specific GPC3 mutations, and the use of model organisms should rapidly expand the understanding of this complex disorder.

Wilms' tumor and related abnormalities in the fetus and newborn

Mesoblastic nephroma, a benign tumor, is the most common renal neoplasm in neonates. Wilms' tumor (WT) may occur in newborn infants, but is more common in older children. The molecular genetics of WT involves one or more genes located on Chromosome #11 and probably other locations not yet elicidated. Germline mutations cause less than 5% of WTs; most WTs are sporadic. Precursor lesions to WT called nephrogenic rests may be detected before evolution to WT by imaging studies. Developmental anomalies comprising several different syndromes are associated with nephrogenic rests and predisposition to WT. Prospective surveillance for WT may be feasible in high risk infants identified on the basis of physical findings followed by testing for predisposing gene defects and periodic imaging of the kidneys and other organs at risk until the period of risk has ended.

Screening for Wilms tumor in children with Beckwith-Wiedemann syndrome or idiopathic hemihypertrophy

BACKGROUND

Children with Beckwith-Wiedemann syndrome and idiopathic hemihypertrophy (BWS/HH) are at increased risk for developing Wilms tumor and screening with abdominal sonography is frequently recommended. However, there is a paucity of published data supporting this strategy. The purpose of this study was to determine whether sonographic screening at intervals of 4 months or less reduced the proportion of late-stage Wilms Tumor (WT) in children with BWS/HH.

PROCEDURE

A case series analysis was employed to compare the proportion of late-stage (stage III or IV) Wilms tumor in patients with BWS/HH who were screened with sonography (n = 15) to the proportion of late-stage Wilms tumor in unscreened patients with BWS/HH (n = 59). Patients were identified from the BWS Registry and from previously published studies. Screened patients had sonograms at intervals of 4 months or less.

RESULTS

None of the 12 screened children with Wilms tumor had late-stage disease, whereas 25 of 59 (42%) of unscreened children had late-stage Wilms tumor, a difference that was statistically significant (P < 0.003). Three children had false positive screening studies. They were operated on for suspected Wilms tumor but the lesions proved to be complicated renal cysts (n = 2) or nephroblastomatosis (n = 1).

CONCLUSIONS

This study suggests that children with BWS/HH may benefit from screening sonograms at intervals of 4 months or less. However, false positive screening exams may result in unnecessary surgery. Given the rarity of BWS/HH, a larger, prospective international screening study is necessary to determine if the benefits of screening outweigh the risks.

Outcome and cost analysis of operative versus nonoperative management of neonatal multicystic dysplastic kidneys

PURPOSE

We determine whether nephrectomy or observation is the more appropriate treatment of neonates with multicystic dysplastic kidney in terms of medical care and cost-effectiveness.

MATERIALS AND METHODS

We retrospectively reviewed our 10-year clinical experience with 17 female and 32 male neonates presenting with multicystic dysplastic kidney who were followed with serial renal ultrasound. The literature also was reviewed.

RESULTS

Nephrectomy was performed in 12 patients (24%) for various reasons, of which family request at concomitant surgery was the most common (7). No kidney was removed due to hypertension or tumor. In the remaining 37 patients followup continues (mean 42 months) with involution developing in 9 multicystic dysplastic kidneys (24%) and 9 patients (24%) lost to followup. The total cost of 1-hour outpatient simple nephrectomy was estimated at $5,000 to $7,000 and, when performed as a concomitant procedure, it cost $2,000 to $5,000, the equivalent charges incurred for 17 to 28 serial ultrasound studies performed by a radiologist. Our review of the literature revealed that children with multicystic dysplastic kidney are at minimal risk for hypertension, pain and infection. The most important reason to perform screening renal ultrasound in this condition is to detect earlier stage Wilms tumor (3 to 10-fold the general pediatric population risk of 1/10,000 cases). With a maximum risk of 0.1% for Wilms tumor controversy exists as to whether any screening program is necessary. When screening is instituted, options include monthly parental abdominal palpation versus serial renal ultrasound. Because Wilms tumor has a rapid growth rate, when screening renal ultrasound is instituted, it must be performed no less than every 3 months until age 8 years (total of 32 studies) to screen effectively for early stage tumors.

CONCLUSIONS

The risks associated with multicystic dysplastic kidney are slight. Early nephrectomy is more cost-effective than observation in neonates with multicystic dysplastic kidney only when observation involves screening with ultrasonography every 3 months until age 8 years. Extensive parental counseling should be provided on the slight but definite risks of this condition.

Risk of cancer during the first four years of life in children from The Beckwith-Wiedemann Syndrome Registry

To determine the incidence and relative risk (RR) of cancer in children with Beckwith-Wiedemann syndrome (BWS), children with BWS were followed up from birth until death, diagnosis of cancer, fourth birthday, or last day of follow-up. A total of 183 children with BWS were followed up for 482 person-years. The end points were incidence of cancer, RR of cancer, and RR associated with specific BWS phenotypic features. Thirteen children were identified with cancers before the fourth year of life in comparison with fewer than one cancer expected in this group on the basis of general population rates over the same period. The average annual incidence of cancer in the first 4 years of life was 0.027 cancer per person-year. The RR of Wilms tumor (RR = 816; 95% confidence interval [CI], 359-1156), neuroblastoma (RR = 197; 95% CI, 22-711), and hepatoblastoma (RR = 2280; 95% CI, 928-11,656) were statistically significant. Asymmetry of the limbs (hemihypertrophy) was the only clinical feature associated with an increased RR of cancer (RR = 4.6; 95% CI, 1.5-14.2). Given the high incidence of cancer in infancy and early childhood of patients with BWS, a prospective study is warranted to address the utility of screening for cancer.