Treatment of relapsed Wilms tumors: lessons learned

Bevacizumab-containing treatment for relapsed or refractory Wilms tumor

INTRODUCTION

Angiogenesis is critical for tumor growth and metastasis. Bevacizumab is an antiangiogenic drug used to treat various adult and childhood solid tumors. Its potential efficacy in Wilms tumor (WT) with poor prognosis is not established.

AREAS COVERED

The response to bevacizumab-containing regimens in relapsed or refractory WT was reviewed in available literature. Searches were conducted using PubMed, Scopus, and ClinicalTrials.gov databases. Eight papers were identified, published between 2007 and 2020, including six treatment regimens, predominantly vincristine, irinotecan, and bevacizumab (VIB) ± temozolomide (VITB). Among 16 evaluable patients, there were two complete responses, seven partial responses, five patients achieved stable disease (SD), and two patients had progressive disease. Objective responses (OR) were observed in 56% of all cases. OR or SD was observed in 89% (8/9) patients who received VIB/VITB. Bevacizumab was generally well tolerated. Related toxicities included hypertension, proteinuria, and delayed wound healing.

EXPERT OPINION

This review suggests potential effectiveness and good tolerability of bevacizumab in the setting of relapsed/refractory WT when used in combination with other drugs. Such combination therapies may serve as a bridging treatment option to other interventions and more personalized treatment options in the future; however, focused trials are needed to obtain additional evidence.

N6-methyladenosine modification of circMARK2 enhances cytoplasmic export and stabilizes LIN28B, contributing to the progression of Wilms tumor

BACKGROUND

The potential involvement of circular RNAs (circRNAs) and N6-methyladenosine (m6A) modification in the progression of Wilms tumor (WT) has not been fully elucidated. This study investigates the regulatory mechanisms and clinical significance of m6A-modified circMARK2 and its role in WT progression.

METHODS

We identified dysregulated circRNAs through deep sequencing and validated their expression by qRT-PCR in WT tissues. The biological functions of circMARK2 were assessed using clone formation, transwell migration, and orthotopic animal models. To dissect the underlying mechanisms, we employed RNA immunoprecipitation, RNA pull-down, dual-luciferase reporter assays, Western blotting, and immunofluorescence and immunohistochemical staining.

RESULTS

CircMARK2, upregulated in WT tissues, was found to be m6A-modified and promoted cytoplasmic export. It facilitated WT progression by stabilizing LIN28B mRNA through the circMARK2/IGF2BP2 interaction. In vitro and in vivo studies demonstrated that circMARK2 enhances the malignant behavior of WT cells. Clinically, higher circMARK2 levels in tumor tissues of WT patients were linked to increased tumor aggressiveness and reduced survival rates.

CONCLUSIONS

Our study provides the first comprehensive evidence that m6A-modified circMARK2 contributes to WT progression by enhancing LIN28B mRNA stability, promoting cellular aggressiveness. CircMARK2 emerges as a potential biomarker for prognosis and a promising target for therapeutic intervention in WT, underscoring the clinical relevance of m6A modification in pediatric renal cancer.

Wnt/β-Catenin Signaling Pathway in Pediatric Tumors: Implications for Diagnosis and Treatment

The evolutionarily conserved Wnt signaling has a significant and diverse role in maintaining cell homeostasis and tissue maintenance. It is necessary in the regulation of crucial biological functions such as embryonal development, proliferation, differentiation, cell fate, and stem cell pluripotency. The deregulation of Wnt/β-catenin signaling often leads to various diseases, including cancer and non-cancer diseases. The role of Wnt/β-catenin signaling in adult tumors has been extensively studied in literature. Although the Wnt signaling pathway has been well explored and recognized to play a role in the initiation and progression of cancer, there is still a lack of understanding on how it affects pediatric tumors. This review discusses the recent developments of this signaling pathway in pediatric tumors. We also focus on understanding how different types of variations in Wnt signaling pathway contribute to cancer development and provide an insight of tissue specific mutations that lead to clinical progression of these tumors.

Advances in the clinical management of high-risk Wilms tumors

Outcomes are excellent for the majority of patients with Wilms tumors (WT). However, there remain WT subgroups for which the survival rate is approximately 50% or lower. Acknowledging that the composition of this high-risk group has changed over time reflecting improvements in therapy, we introduce the authors' view of the historical and current approach to the classification and treatment of high-risk WT. For this review, we consider high-risk WT to include patients with newly diagnosed metastatic blastemal-type or diffuse anaplastic histology, those who relapse after having been initially treated with three or more different chemotherapeutics, or those who relapse more than once. In certain low- or low middle-income settings, socio-economic factors expand the definition of what constitutes a high-risk WT. As conventional therapies are inadequate to cure the majority of high-risk WT patients, advancement of laboratory and early-phase clinical investigations to identify active agents is urgently needed.

Advances in the clinical management of high-risk Wilms tumors

Outcomes are excellent for the majority of patients with Wilms tumors (WT). However, there remain WT subgroups for which the survival rate is approximately 50% or lower. Acknowledging that the composition of this high-risk group has changed over time reflecting improvements in therapy, we introduce the authors' view of the historical and current approach to the classification and treatment of high-risk WT. For this review, we consider high-risk WT to include patients with newly diagnosed metastatic blastemal-type or diffuse anaplastic histology, those who relapse after having been initially treated with three or more different chemotherapeutics, or those who relapse more than once. In certain low- or low middle-income settings, socio-economic factors expand the definition of what constitutes a high-risk WT. As conventional therapies are inadequate to cure the majority of high-risk WT patients, advancement of laboratory and early-phase clinical investigations to identify active agents is urgently needed.

Immune-related gene signature associates with immune landscape and predicts prognosis accurately in patients with Wilms tumour

Wilms tumour (WT) is the most common kidney malignancy in children. Chemoresistance is the leading cause of tumour recurrence and poses a substantial therapeutic challenge. Increasing evidence has underscored the role of the tumour immune microenvironment (TIM) in cancers and the potential for immunotherapy to improve prognosis. There remain no reliable molecular markers for reflecting the immune landscape and predicting patient survival in WT. Here, we examine differences in gene expression by high-throughput RNA sequencing, focused on differentially expressed immune-related genes (IRGs) based on the ImmPort database. Via univariate Cox regression analysis and Lasso-penalized Cox regression analysis, IRGs were screened out to establish an immune signature. Kaplan-Meier curves, time-related ROC analysis, univariate and multivariate Cox regression studies, and nomograms were used to evaluate the accuracy and prognostic significance of this signature. Furthermore, we found that the immune signature could reflect the immune status and the immune cell infiltration character played in the tumour microenvironment (TME) and showed significant association with immune checkpoint molecules, suggesting that the poor outcome may be partially explained by its immunosuppressive TME. Remarkably, TIDE, a computational method to model tumour immune evasion mechanisms, showed that this signature holds great potential for predicting immunotherapy responses in the TARGET-wt cohort. To decipher the underlying mechanism, GSEA was applied to explore enriched pathways and biological processes associated with immunophenotyping and Connectivity map (CMap) along with DeSigN analysis for drug exploration. Finally, four candidate immune genes were selected, and their expression levels in WT cell lines were monitored via qRT-PCR. Meanwhile, we validated the function of a critical gene, NRP2. Taken together, we established a novel immune signature that may serve as an effective prognostic signature and predictive biomarker for immunotherapy response in WT patients. This study may give light on therapeutic strategies for WT patients from an immunological viewpoint.

Circulating Tumor DNA as a Biomarker in Patients With Stage III and IV Wilms Tumor: Analysis From a Children's Oncology Group Trial, AREN0533

PURPOSE

The utility of circulating tumor DNA (ctDNA) analyses has not been established in the risk stratification of Wilms tumor (WT). We evaluated the detection of ctDNA and selected risk markers in the serum and urine of patients with WT and compared findings with those of matched diagnostic tumor samples.

PATIENTS AND METHODS

Fifty of 395 children with stage III or IV WT enrolled on Children's Oncology Group trial AREN0533 had banked pretreatment serum, urine, and tumor available. Next-generation sequencing was used to detect ctDNA. Copy-number changes in 1q, 16q, and 1p, and single-nucleotide variants in serum and urine were compared with tumor biopsy data. Event-free survival (EFS) was compared between patients with and without ctDNA detection.

RESULTS

ctDNA was detected in the serum of 41/50 (82%) and in the urine in 13/50 (26%) patients. Agreement between serum ctDNA detection and tumor sequencing results was as follows: 77% for 1q gain, 88% for 16q deletions, and 70% for 1p deletions, with ĸ-coefficients of 0.56, 0.74, and 0.29, respectively. Sequencing also demonstrated that single-nucleotide variants detected in tumors could be identified in the ctDNA. There was a trend toward worse EFS in patients with ctDNA detected in the serum (4-year EFS 80% v 100%, P = .14).

CONCLUSION

ctDNA demonstrates promise as an easily accessible prognostic biomarker with potential to detect tumor heterogeneity. The observed trend toward more favorable outcome in patients with undetectable ctDNA requires validation. ctDNA profiling should be further explored as a noninvasive diagnostic and prognostic tool in the risk-adapted treatment of patients with WT.

Silk Fibroin Hydrogel Reinforced With Magnetic Nanoparticles as an Intelligent Drug Delivery System for Sustained Drug Release

Due to the well-known biocompatibility, tunable biodegradability, and mechanical properties, silk fibroin hydrogel is an exciting material for localized drug delivery systems to decrease the therapy cost, decrease the negative side effects, and increase the efficiency of chemotherapy. However, the lack of remote stimuli response and active drug release behavior has yet to be analyzed comparatively. In this study, we developed magnetic silk fibroin (SF) hydrogel samples through the facile blending method, loaded with doxorubicin hydrochloride (DOX) and incorporated with different concentrations of iron oxide nanoparticles (IONPs), to investigate the presumable ability of controlled and sustained drug release under the various external magnetic field (EMF). The morphology and rheological properties of SF hydrogel and magnetic SF hydrogel were compared through FESEM images and rheometer analysis. Here, we demonstrated that adding magnetic nanoparticles (MNPs) into SFH decreased the complex viscosity and provided a denser porosity with a bigger pore size matrix structure, which allowed the drug to be released faster in the absence of an EMF. Release kinetic studies show that magnetic SF hydrogel could achieve controlled release of DOX in the presence of an EMF. Furthermore, the drug release from magnetic SF hydrogel decreased in the presence of a static magnetic field (SMF) and an alternating magnetic field (AMF), and the release rate decreased even more with the higher MNPs concentration and magnetic field strength. Subsequently, Wilms’ tumor and human fibroblast cells were cultured with almost the same concentration of DOX released in different periods, and cell viability was investigated using MTT assay. MTT results indicated that the Wilms’ tumor cells were more resistant to DOX than the human fibroblasts, and the IC50 values were calculated at 1.82 ± 0.001 and 2.73 ± 0.004 (μg/ml) for human fibroblasts and Wilms’ tumor cells, respectively. Wilms’ tumor cells showed drug resistance in a higher DOX concentration, indicating the importance of controlled drug delivery. These findings suggest that the developed magnetic SFH loaded with DOX holds excellent potential for intelligent drug delivery systems with noninvasive injection and remotely controlled abilities.

The Regulatory Network and Role of the circRNA-miRNA-mRNA ceRNA Network in the Progression and the Immune Response of Wilms Tumor Based on RNA-Seq

Circular RNA (circRNA), which is a newly discovered non-coding RNA, has been documented to play important roles in miRNA sponges, and the dysregulation of which is involved in cancer development. However, circRNA expression profiles and their role in initiation and progression of Wilms tumor (WT) remain largely unclear at present. Here, we used paired WT samples and high-throughput RNA sequencing to identify differentially expressed circRNAs (DE-circRs) and mRNAs (DE-mRs). A total of 314 DE-circRs and 1612 DE-mRs were identified. The expression of a subset of differentially expressed genes was validated by qRT–PCR. A complete circRNA-miRNA-mRNA network was then constructed based on the common miRNA targets of DE-circRs and DE-mRs identified by miRanda prediction tool. The Gene set enrichment analysis (GSEA) indicated that several signaling pathways involving targeted DE-mRs within the ceRNA network were associated with cell cycle and immune response, which implies their participation in WT development to some extent. Subsequently, these targeted DE-mRs were subjected to implement PPI analysis and to identify 10 hub genes. Four hub genes were closely related to the survival of WT patients. We then filtered prognosis-related hub genes by Cox regression and least absolute shrinkage and selection operator (LASSO) regression analysis to construct a prognosis-related risk score system based on a three-gene signature, which showed good discrimination and predictive ability for WT patient survival. Additionally, we analyzed the mutational landscape of these genes and the associations between their expression levels and those of immune checkpoint molecules and further demonstrated their potential impact on the efficacy of immunotherapy. qRT–PCR and western blotting (WB) analysis were used to validate key differentially expressed molecules at the RNA and protein levels, respectively. Besides these, we selected a key circRNA, circEYA1, for function validation. Overall, the current study presents the full-scale expression profiles of circRNAs and the circRNA-related ceRNA network in WT for the first time, deepening our understanding of the roles and downstream regulatory mechanisms of circRNAs in WT development and progression. We further constructed a useful immune-related prognostic signature, which could improve clinical outcome prediction and guide individualized treatment.

Identification of a 12-Gene Signature and Hub Genes Involved in Kidney Wilms Tumor via Integrated Bioinformatics Analysis

Wilms tumor (WT), also known as nephroblastoma, is a rare primary malignancy in all kinds of tumor. With the development of second-generation sequencing, the discovery of new tumor markers and potential therapeutic targets has become easier. This study aimed to explore new WT prognostic biomarkers. In this study, WT-miRNA datasets GSE57370 and GSE73209 were selected for expression profiling to identify differentially expressed genes. The key gene miRNA, namely hsa-miR-30c-5p, was identified by overlapping, and the target gene of candidate hsa-miR-30c-5p was predicted using an online database. Furthermore, 384 genes were obtained by intersecting them with differentially expressed genes in the TARGET-WT database, and the genes were analyzed for pathway and functional enrichment. Kaplan–Meier survival analysis of the 384 genes yielded a total of 25 key genes associated with WT prognosis. Subsequently, a prediction model with 12 gene signatures (BCL6, CCNA1, CTHRC1, DGKD, EPB41L4B, ERRFI1, LRRC40, NCEH1, NEBL, PDSS1, ROR1, and RTKN2) was developed. The model had good predictive power for the WT prognosis at 1, 3, and 5 years (AUC: 0.684, 0.762, and 0.774). Finally, ERRFI1 (hazard ratios [HR] = 1.858, 95% confidence intervals [CI]: 1.298–2.660) and ROR1 (HR = 0.780, 95% CI: 0.609–0.998) were obtained as independent predictors of prognosis in WT patients by single, multifactorial Cox analysis.

High-dose chemotherapy followed by autologous stem cell rescue in Wilms tumors: French report on toxicity and efficacy

BACKGROUND

Heterogeneous data have been reported on high-dose chemotherapy (HDCT) with autologous stem cell rescue (ASCR) in Wilms tumors (WTs). We aimed to define its safety and efficacy in the French cohort, and to compare this management to current international recommendations.

METHODS

Data prospectively collected from children, adolescents, and young adults with WT treated with HDCT/ASCR between 2000 and 2016 in French centers were retrospectively analyzed. Toxicity was reported according to CTCAE v4.03.

RESULTS

Fifty-four patients received HDCT/ASCR (first line, n = 13; recurrence, n = 41). Their median age at the time of ASCR was 5.3 years (range 2.2-21.6). Main nonhematological acute grades 3-4 toxicities were digestive and renal. No significant difference of toxicity rate was observed among HDCT regimens and schedules. Two patients died shortly after ASCR (renal and multiorgan failure), and one heavily pretreated patient died of late respiratory failure. The selection criteria applied to define those patients eligible for HDCT/ASCR retrospectively matched to those currently used in the International Society of Pediatric Oncology (SIOP) UMBRELLA protocol for 38 patients, with encouraging survival rates compared to published data. The objective response rate to HDCT was 21%, with a disease control rate after HDCT of 85%. After a median follow-up of 7 years, the 5-year event-free survival (EFS) and overall survival (OS) were 54% (95% CI: 32%-76%) and 62% (95% CI: 31%-82%) for frontline patients, and 57% (95% CI: 39%-71%) and 69% (95% CI: 52%-81%) at recurrence.

CONCLUSION

HDCT was feasible and showed encouraging results in well-defined settings. Data from the current prospective protocol will help to better evaluate HDCT impact on survival.

Outcome of SIOP patients with low- or intermediate-risk Wilms tumour relapsing after initial vincristine and actinomycin-D therapy only - the SIOP 93-01 and 2001 protocols

PURPOSE

Society of International Pediatric Oncology - Renal Tumor Study Group (SIOP-RTSG) treatment recommendations for relapsed Wilms tumour (WT) are stratified by the intensity of first-line treatment. To explore the evidence for the treatment of patients relapsing after vincristine and actinomycin-D (VA) treatment for primary WT, we retrospectively evaluated rescue treatment and survival of this patient group.

PATIENTS AND METHODS

We included 109 patients with relapse after VA therapy (no radiotherapy) for stage I-II primary low- or intermediate-risk WT from the SIOP 93-01 and SIOP 2001 studies. Univariate Cox regression analysis was performed to study the effect of relapse treatment intensity on event-free survival (EFS) and overall survival (OS). Relapse treatment intensity was classified into vincristine, actinomycin-D, and either doxorubicin or epirubicin (VAD), and more intensive therapies (ifosfamide/carboplatin/etoposide [ICE]/≥ 4 drugs/high-dose chemotherapy with haematopoietic stem cell transplantation [HD HSCT]).

RESULTS

Relapse treatment regimens included either VAD, or cyclophosphamide/carboplatin/etoposide/doxorubicin (CyCED), or ICE backbones. Radiotherapy was administered in 62 patients and HD HSCT in 15 patients. Overall, 5-year EFS and OS after relapse were 72.3% (95% confidence interval [CI]: 64.0-81.6%) and 79.3% (95% CI: 71.5-88.0%), respectively. Patients treated with VAD did not fare worse when compared with patients treated with more intensive therapies (hazard ratio EFS: 0.611 [95% CI: 0.228-1.638] [p-value = 0.327] and hazard ratio OS: 0.438 [95% CI: 0.126-1.700] [p-value = 0.193]).

CONCLUSION

Patients with relapsed WT after initial VA-only treatment showed no inferior EFS and OS when treated with VAD regimens compared with more intensive rescue regimens. A subset of patients relapsing after VA may benefit from less intensive rescue treatment than ICE/CyCED-based regimens and deserve to be pinpointed by identifying additional (molecular) prognostic factors in future studies.

Myelin and lymphocyte protein serves as a prognostic biomarker and is closely associated with the tumor microenvironment in the nephroblastoma

Nephroblastoma, also known as Wilms' tumor (WT), is the most common renal tumor that occurs in children. Although the efficacy of treatment has been significantly improved by a series of comprehensive treatments, some patients still have poor prognosis. Myelin and lymphocyte (MAL) protein, a highly hydrophobic integrated membrane‐bound protein, has been implicated in many tumors and is also closely linked to kidney development. However, the relationship between MAL and WT has not yet been elucidated. Therefore, we attempted to evaluate the feasibility of MAL as a promising prognosis factor for WT. The differential expression of MAL was investigated using TARGET database and was verified using the Gene Expression Omnibus database and real‐time quantitative PCR. The prognostic ability of MAL was determined using Kaplan–Meier and Cox regression analyses. Pearson correlation analysis was applied to explore the relationship between MAL expression and methylation sites. The ESTIMATE and CIBERSORT algorithms showed that MAL expression was associated with the WT tumor microenvironment. Gene Set Enrichment Analysis (GSEA) indicated that multiple signaling pathways closely associated with tumorigenesis were differentially enriched between the high‐ and low‐MAL groups. In conclusion, our study comprehensively explored the potential of MAL as a prognosis factor for WT. Meanwhile, we also demonstrated that MAL, as a prognostic factor for WT, may be closely related to the tumor microenvironment.

Wilms tumour

Wilms tumour (WT) is a childhood embryonal tumour that is paradigmatic of the intersection between disrupted organogenesis and tumorigenesis. Many WT genes play a critical (non-redundant) role in early nephrogenesis. Improving patient outcomes requires advances in understanding and targeting of the multiple genes and cellular control pathways now identified as active in WT development. Decades of clinical and basic research have helped to gradually optimize clinical care. Curative therapy is achievable in 90% of affected children, even those with disseminated disease, yet survival disparities within and between countries exist and deserve commitment to change. Updated epidemiological studies have also provided novel insights into global incidence variations. Introduction of biology-driven approaches to risk stratification and new drug development has been slower in WT than in other childhood tumours. Current prognostic classification for children with WT is grounded in clinical and pathological findings and in dedicated protocols on molecular alterations. Treatment includes conventional cytotoxic chemotherapy and surgery, and radiation therapy in some cases. Advanced imaging to capture tumour composition, optimizing irradiation techniques to reduce target volumes, and evaluation of newer surgical procedures are key areas for future research.

Prognostic Factors for Wilms Tumor Recurrence: A Review of the Literature

Simple Summary

A Wilms tumor is a childhood kidney tumor. In high-income countries, 90% of patients with this tumor survive. However, the tumor recurs in 15% of patients. It is important to identify the patients at risk of recurrence in order to adjust treatment in such a way that recurrence may potentially be prevented. However, we are currently unable to determine precisely which patients are at risk of recurrence. Therefore, we present an overview of factors that influence the risk of recurrence, also known as prognostic factors. These factors range from patient-, tumor- and treatment-related characteristics to geographic and socioeconomic factors. In addition to these factors, biological markers, such as genetic alterations, should be studied more intensively as these markers may be able to better identify patients at risk of tumor recurrence.

Abstract

In high-income countries, the overall survival of children with Wilms tumors (WT) is ~90%. However, overall, 15% of patients experience tumor recurrence. The adverse prognostic factors currently used for risk stratification (advanced stage, high risk histology, and combined loss of heterozygosity at 1p and 16q in chemotherapy-naïve WTs) are present in only one third of these cases, and the significance of these factors is prone to change with advancing knowledge and improved treatment regimens. Therefore, we present a comprehensive, updated overview of the published prognostic variables for WT recurrence, ranging from patient-, tumor- and treatment-related characteristics to geographic and socioeconomic factors. Improved first-line treatment regimens based on clinicopathological characteristics and advancing knowledge on copy number variations unveil the importance of further investigating the significance of biological markers for WT recurrence in international collaborations.

Locoregional control using highly conformal flank target volumes and volumetric-modulated arc therapy in pediatric renal tumors: Results from the Dutch national cohort

BACKGROUND AND PURPOSE

In pediatric renal tumors, conventional two opposing photon beams have been used to cover the postoperative flank target volume for decades. This single center study describes the locoregional outcome using highly conformal flank target volumes adjusted for postoperative changes and intra-fraction motion combined with Volumetric-Modulated Arc Therapy (VMAT).

MATERIALS AND METHODS

Between 01-2015 and 12-2019, 36/161 newly diagnosed patients with renal tumors underwent flank only irradiation (n = 30) or flank + whole lung irradiation (n = 6) using highly conformal target volumes in line with the SIOP-RTSG consensus statement. VMAT consisted of full-arc 10MV photon beams optimized for constraints of the organs at risk. In case of locoregional relapses, image co-registration and dose reconstruction was performed. Each relapse was classified as either 'infield' (V95%_relapse: ≥99.0%), 'marginal' (V95%_relapse: 20.0-98.9%) or 'outfield' (V95%_relapse: 0-19.9%).

RESULTS

At a median follow-up from diagnosis of 3.1 years (range:0.4-5.7), the estimated 2-year Locoregional Control Rate, Disease-Free Interval and Overall Survival were 94%, 91% and 94%, respectively. Locoregional relapse was observed in two patients. One patient had a combined tumor bed and regional recurrence, classified as infield (V95%_relapse: 100%) and outfield (V95%_relapse: 1.2%). The second patient had a regional relapse in the inferior vena cava classified as marginal recurrence (V95%_relapse: 93%). Relapses would not have been adequately covered by conventional beams.

CONCLUSIONS

This single center analysis provides encouraging evidence that excellent locoregional control can be obtained by using highly conformal flank target volumes with VMAT in pediatric renal tumors. The safety of this approach will be validated in a prospective multicenter study.

Identification of the potential novel biomarkers as susceptibility gene for Wilms tumor

Background

Wilms tumor (WT) is the most common malignant renal tumor in children. The aim of this study was to identify potential susceptibility gene of WT for better prognosis.

Methods

Weighted gene coexpression network analysis is used for the detection of clinically important biomarkers associated with WT.

Results

In the study, 59 tissue samples from National Cancer Institute were pretreated for constructing gene co-expression network, while 224 samples also downloaded from National Cancer Institute were used for hub gene validation and module preservation analysis. Three modules were found to be highly correlated with WT, and 44 top hub genes were identified in these key modules eventually. In addition, both the module preservation analysis and gene validation showed ideal results based on other dataset with 224 samples. Meanwhile, Functional enrichment analysis showed that genes in module were enriched to sister chromatid cohesion, cell cycle, oocyte meiosis.

Conclusion

In summary, we established a gene co-expression network to identify 44 hub genes are closely to recurrence and staging of WT, and 6 of these hub genes was closely related to the poor prognosis of patients. Our findings revealed that those hub genes may be used as potential susceptibility gene for clinical diagnosis and prognosis of this tumor.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08034-w.

Many faces of Wilms Tumor: Recent advances and future directions

Background

Wilms’ tumor (WT) is the most frequently occurring paediatric renal tumor and is one of the most treatment-responsive tumors. A tumor-suppressor gene and other genetic abnormalities have been implicated in its etiology. In addition, patients with many congenital anomalies, such as Beckwith-Wiedemann syndrome, WAGR syndrome and Denys-Drash syndrome, have an increased risk of WT.

Methods and results

Two large collaborative groups – National Wilms Tumor Study Group (NWTSG)/Children's Oncology Group (COG) and The International Society of Paediatric Oncology (SIOP) have laid down the guidelines for standardized treatment of WT, though differing in the diagnostic and therapeutic approach. The major difference in the two guidelines is the timing of surgery: SIOP recommends using preoperative chemotherapy and NWTSG/COG prefers primary surgery before any adjuvant treatments. Both these groups currently aim at intensifying treatment for patients with poor prognosticators while appropriating the therapy to reduce long-term complications for those with favourable prognostic features. As the survival rate has now reached 90%, the primary objectives of the physician are to perform nephron-sparing surgery in selected cases and to reduce the dosage and duration of chemotherapy and radiotherapy in appropriate cases. The purpose of this review is to present current standards of diagnosis and treatment of WT around the world.

Conclusion

Further studies in future should be done to highlight the use of chemotherapy and radiotherapy under risk-stratified strategies. Further improvement in survival of these children can only be achieved by increasing awareness, early recognition, appropriate referral, and a multidisciplinary approach.

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o Most of the patients with WT have good prognosis.

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o Multimodality treatment and multidisciplinary care are the major contributors for an improved prognosis.

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o Further studies should be done on usage of chemotherapy and radiotherapy under more accurate risk-stratified strategies and to decrease the late effects of surgery.

Unmet needs for relapsed or refractory Wilms tumour: Mapping the molecular features, exploring organoids and designing early phase trials - A collaborative SIOP-RTSG, COG and ITCC session at the first SIOPE meeting

Wilms tumour (WT) accounts for about 6% of all childhood cancers and overall survival of WT is about 90% in international protocols. However, for WT subgroups with much poorer prognoses, i.e. typically high-risk (unfavorable) histology and/or relapse, there is an unmet need to better understand the biology of WT and to translate biological findings into clinics through early phase clinical trials that evaluate innovative therapies. The main challenges are the small numbers of children suitable for early phase trials, the genetic heterogeneity of WT and the low number of somatic mutations that are currently considered 'druggable'. Accordingly, a joint meeting between clinical and biology experts from the international cooperative groups of the Renal Tumour Study Group of the International Society of Paediatric Oncology, the Renal Tumour Committee of the Children's Oncology Group and the European Innovative Therapies for Children with Cancer consortium and parents representatives was organised during the first SIOPE meeting in Prague, 2019. We reviewed WT molecular features, ongoing/planned early phase trials and explored available knowledge on organoid technology. The key messages were: (1) relapsed WT should undergo whenever possible thorough molecular characterization and be enrolled in protocols or trials with systematic data collecting and reporting; (2) WT displays few known 'actionable' targets and currently no novel agent has appeared promising; (3) we need to improve the enrolment rate of WT candidates in early phase trials especially for the relatively small subgroup of relapses with an adverse prognostic signature; (4) despite some agnostic early phase trials existing, development of WT-focused trials are warranted; (5) growing organoids with parallel testing of drug panels seems feasible and may direct individual treatment and encourage clinical researchers to incorporate the most promising agents into early phase trials.

Lithocholic bile acid induces apoptosis in human nephroblastoma cells: a non-selective treatment option

Lithocholic bile acid (LCA) has been reported to selectively kill cancer cells within many tumor cell lines including neuroblastoma or glioblastoma. Wilms’ tumor shares similarities with neuro- and glioblastoma. Hence, the aim of the study was to evaluate the effects of LCA on nephroblastoma. To test the effects of LCA, nephroblastoma cell line WT CLS1 was used. SK NEP1 was tested as well. It was originally classified as a nephroblastoma cell line but was meanwhile reclassified as an ewing sarcoma cell line. As control cell lines HEK 293 from embryonic kidney and RC 124 from adult kidney tissue as well as podocytes were used. The effects were evaluated using proliferation assay, caspase activity assay, FACS and Western blot. LCA showed a dose and time-dependent selective effect inducing apoptosis in nephroblastoma cells. However, these effects were not limited to the nephroblastoma cell line but also affected control kidney cell lines and the sarcoma cells; only podocytes are significantly less affected by LCA (at dosages < 200 µm). There were no significant differences regarding the TGR5 receptor expression. The study showed that LCA has a strong, yet unselective effect on all used in vitro cell-lines, sparing the highly differentiated podocytes in lower concentrations. Further studies are needed to verify our results before dismissing LCA as an anti-cancer drug.

Comprehensive analysis of the long non-coding RNA-associated competitive endogenous RNA network reveals novel prognostic biomarkers in Wilms' tumor

Wilms' tumor (WT) is one of the most common types of renal carcinoma in children. The aim of the present study was to construct a competitive endogenous RNA (ceRNA) regulation network and explore novel prognostic biomarkers for WT. The expression profiles were downloaded from The Cancer Genome Atlas database to identify differentially expressed RNAs (DERNAs). Based on the interactions between microRNAs (miRNAs) and mRNAs/long non-coding RNAs (lncRNAs), a ceRNA network was constructed. Functional enrichment analyses were subsequently conducted to explore the functions of the ceRNA-associated DEmRNAs. Survival analysis was performed to screen for prognosis-associated RNAs and the χ² test was used to assess the associations between prognosis-associated RNA expression and histology classification/clinical staging. The present study identified 1,784 lncRNAs, 114 miRNAs and 3,337 mRNAs, which were abnormally expressed in WT compared with that in normal samples. By prediction, pairing and network analysis, a ceRNA network consisting of 38 DElncRNAs, 18 DEmiRNAs and 99 DEmRNAs was established. These DEmRNAs were significantly enriched in pathways associated with the occurrence and development of WT. By combining the expression data with survival analysis, seven prognosis-associated RNAs were identified (P<0.05). Of these seven RNAs, two (zinc finger and BTB domain containing 4; and deleted in lymphocytic leukemia 2) were significantly associated with clinical staging and histology classification. Lastly, the expression levels of the seven RNAs were verified in the Gene Expression Omnibus database. The present study revealed that 7 RNAs might be considered as novel prognostic biomarkers and potential treatment targets for therapy in WT. In addition, the ceRNA regulation network could provide novel strategies for further studies on lncRNAs and miRNAs in WT.

Relapsed Wilms' tumor in pediatric patients: challenges in low- to middle-income countries-a single-center experience

BACKGROUND

Wilms' tumor (WT) affects one in 10,000 children and accounts for 5% of all childhood cancers. Although the overall relapse rate for children with WT has decreased to less than 15 %, the overall survival for patients with recurrent disease remains poor at approximately 50 %. The aim of the study to evaluate the outcome of relapsed Wilms' tumor pediatric patients treated at the National Cancer Institute (NCI), Egypt, between January 2008 and December 2015.

RESULTS

One hundred thirty (130) patients diagnosed with WT during the study period, thirty (23%) patients had relapsed. The median follow up period was 22.3 months (range 3.6-140 months). The Overall Survival (OS) was 30.9% while the event-free survival (EFS) was 29.8% at a 5-year follow up period. Median time from diagnosis to relapse was 14.4 months. A second complete remission was attained in 18/30 patients (60%). The outcome of the 30 patients; 11 are alive and 19 had died. Three factors in our univariate analysis were prognostically significant for survival after relapse. The first was radiotherapy given after relapse (p = 0.012). The 5-year EFS and OS for the group that received radiotherapy were 41.9% versus 16.7% and 11.1% respectively for those that did not. The second was the state of lymph nodes among patients with local stage III (p = 0.004). Lastly, when risk stratification has been applied retrospectively on our study group, it proved to be statistically significant (p = 0.029).

CONCLUSION

Among relapsed pediatric WT, radiotherapy improved survival at the time of relapse and local stage III with positive lymph nodes had the worst survival among other stage III patients.

Novel therapy for pediatric and adolescent kidney cancer

Pediatric and adolescent renal tumors account for approximately 7% of all new cancer diagnoses in the USA each year. The prognosis and treatment are varied based on factors including the underlying histology and tumor stage, with survival rates ranging from greater than 90% in favorable histology Wilms tumor to almost universally fatal in other disease types, including those patients with advanced stage malignant rhabdoid tumor and renal medullary carcinoma. In recent years, our understanding of the underlying genetic drivers of the different types of pediatric kidney cancer has dramatically increased, opening the door to utilization of new targeted biologic agents alone or in combination with conventional chemotherapy to improve outcomes. Several ongoing clinical trials are investigating the use of a variety of targeted agents in pediatric patients with underlying genetic aberrations. In this manuscript, the underlying biology and early phase clinical trials relevant to pediatric renal cancers are reviewed.

Evaluation of Nephron-Sparing Surgery as Potential Risk Factor for Relapse in Unilateral Wilms Tumor

BACKGROUND

The aim of the study was to assess the prognostic significance of nephron-sparing surgery (NSS) without tumor size limits as a risk factor for relapse in children with unilateral Wilms Tumor (WT).

METHODS

A 28-y retrospective single-center review was performed. Prognostic relevance of age, gender, stage, histology, nephrectomy (N), and NSS was analyzed.

RESULTS

Sixty-nine cases (42 females and 27 males) with WT, off-therapy from 21 to 325 mo after chemotherapy mainly based on the International Society of Pediatric Oncology trials, were treated at our institution. Five cases were excluded (three children with synchronous bilateral WT and two adults with unilateral WT). Of 64 children with unilateral WT, 51 underwent N and 13 NSS without tumor size limits. Indeed, two-thirds of children who underwent NSS presented with a tumor diameter >4 cm. Overall, nine patients (14%) had a relapse (male-to-female ratio = 1:8). Initial surgery was N in eight cases and NSS in another one. Relapse rates in N and NSS groups were 15.7% and 7.7% (P = nonsignificant), respectively; the relapse rates in N and NSS groups were 8.6% and 7.7% (P = nonsignificant) for stages I-II unilateral WT cohort, respectively. On univariate analysis, factors correlated with probability of relapse were unfavorable histology (P < 0.002) and stage III disease (P < 0.01).

CONCLUSIONS

In unilateral WT, NSS, whenever feasible, does not seem to increase the risk of recurrence. A multicenter prospective trial is required to carefully evaluate this risk.

Current treatment for Wilms tumor: COG and SIOP standards

Background

Wilms tumor (WT) is the most common renal malignant tumor in children. It occurs primarily at preschool age. The purpose of this review is to present current standards of diagnosis and treatment of WT around the world.

Data sources

All the recent literature on diagnosis and treatment of WT were searched and reviewed.

Results

Most cases with WT are sporadic. The current survival in patients with WT is high (90%). Involvement of mutidisciplinary collaborative groups in the diagnosis and treatment of WT. National Wilms Tumor Study Group (NWTSG)/Children’s Oncology Group (COG) and The International Society of Paediatric Oncology (SIOP) are two major guidelines used for the current management of WT worldwide. The major difference exists in the two guidelines is the timing of surgery: SIOP recommends using preoperative chemotherapy, and NWTSG/COG prefers using primary surgery before any adjuvant treatments.

Conclusions

Most patients with WT have good overall survival outcomes. Further studies should be highlighted on how to use chemotherapy and radiotherapy under more accurate risk-stratified strategies. Surgeons must be more focusing on how to maximize preoperative and postoperative treatment possibilities for achieving optimal results of patients with WT.

The genetic changes of Wilms tumour

Wilms tumour is the most common renal malignancy of childhood. The disease is curable in the majority of cases, albeit at considerable cost in terms of late treatment-related effects in some children. However, one in ten children with Wilms tumour will die of their disease despite modern treatment approaches. The genetic changes that underpin Wilms tumour have been defined by studies of familial cases and by unbiased DNA sequencing of tumour genomes. Together, these approaches have defined the landscape of cancer genes that are operative in Wilms tumour, many of which are intricately linked to the control of fetal nephrogenesis. Advances in our understanding of the germline and somatic genetic changes that underlie Wilms tumour may translate into better patient outcomes. Improvements in risk stratification have already been seen through the introduction of molecular biomarkers into clinical practice. A host of additional biomarkers are due to undergo clinical validation. Identifying actionable mutations has led to potential new targets, with some novel compounds undergoing testing in early phase trials. Avenues that warrant further exploration include targeting Wilms tumour cancer genes with a non-redundant role in nephrogenesis and targeting the fetal renal transcriptome.

Pharmacotherapeutic Management of Wilms Tumor: An Update

Although differences exist in treatment and risk-stratification strategies for children with Wilms tumor (WT) between the European [International Society of Paediatric Oncology (SIOP)] and American [Children's Oncology Group (COG)] study groups, outcomes are very similar, with an overall survival of > 85%. Future strategies aim to de-intensify treatment and reduce toxicity for children with a low risk of relapse and intensify treatment for children with high-risk disease. For metastatic WT, response of lung nodules to chemotherapy is used as a marker to modify treatment intensity. For recurrent WT, a unified approach based on the use of agents that were not used for primary therapy is being introduced. Irinotecan is being explored as a new strategy in both metastatic and relapsed WT. Introduction of biology-driven approaches to risk stratification and new drug treatments has been slower in WT than in some other childhood cancers. While several new biological pathways have been identified recently in WT, their individual rarity has hampered their translation into clinical utility. Identification of robust prognostic factors requires extensive international collaborative studies because of the low proportion who relapse or die. Molecular profiling studies are in progress that should ultimately improve both risk classification and signposting to more targeted therapies for the small group for whom current therapies fail. Accrual of patients with WT to early-phase trials has been low, and the efficacy of these new agents has so far been very disappointing. Better in vitro model systems to test mechanistic dependence are needed so available new agents can be more rationally prioritized for recruitment of children with WT to early-phase trials.

Management of Denys-Drash syndrome: A case series based on an international survey

Denys-Drash syndrome (DDS), a condition caused by mutations in the tumor-suppressor gene WT-1, is associated with a triad of disorders: ambiguous genitalia, nephrotic syndrome leading to end-stage renal disease (ESRD), and Wilms’ tumor. Given the variable disease course, management is challenging. We aimed to describe the evolution of DDS and the range of management strategies by summarizing the clinical courses of cases collected from a questionnaire sent to the international pediatric nephrology community. 15 respondents provided information on 23 patients; 21 DDS cases were confirmed and analyzed. At DDS diagnosis, 6 patients had a Wilms’ tumor (group A) and 15 had no Wilms’ tumor (group B). Three group A patients had unilateral nephrectomy. Two of these still had renal function, with no second tumor, at 36 months and 16 years of age, and 1 progressed to ESRD. Three had bilateral nephrectomy before ESRD. Eight group B patients progressed to ESRD, all of whom later had all renal tissue removed. Two group B patients subsequently developed a unilateral Wilms’ tumor and had bilateral nephrectomy pre-ESRD. Three had bilateral nephrectomy prior to reaching ESRD without ever having a Wilms’ tumor. Two group B patients remained tumor-free with renal function at last follow-up. Two main management approaches were taken: pre-emptive nephrectomy prior to ESRD and conservative surveillance. Based on the known risks associated with ESRD in infants and young children, the variable course of DDS, and the relatively good prognosis associated with Wilms’ tumor, a guiding principle of preservation of renal function is most logical. Most would advocate bilateral prophylactic nephrectomy after ESRD is reached due to the high tumor risk, which is likely heightened after transplant.

Impact of Surveillance Imaging Modality on Survival After Recurrence in Patients With Favorable-Histology Wilms Tumor: A Report From the Children's Oncology Group

PURPOSE

The use of computed tomography (CT) for routine surveillance to detect recurrence in patients with Wilms tumor (WT) has increased in recent years. The utility of CT, despite increased risk and cost, to improve outcome for these patients is unknown. We conducted a retrospective analysis with patients enrolled in the fifth National Wilms Tumor Study (NWTS-5) to determine if surveillance with CT correlates with improved overall survival (OS) after recurrence compared with chest x-ray (CXR) and abdominal ultrasound (US).

PATIENTS AND METHODS

Overall, 281 patients with recurrent unilateral favorable-histology WT were reviewed to assess how WT recurrence was detected: sign/symptoms (SS), surveillance imaging (SI) with CT scan, or SI with CXR/US.

RESULTS

The estimated 5-year OS rate after relapse was 67% (95% CI, 61% to 72%). Twenty-five percent of recurrences were detected with SS; 48.5%, with CXR/US; and 26.5%, with CT. Patients with SS had a 5-year OS rate of 59% (95% CI, 46% to 72%) compared with 70% (95% CI, 63% to 77%; P = .23) for those detected by SI. Recurrences detected by CT had a shorter median time from diagnosis to recurrence (0.60 years) compared with SS (0.91 years) or CXR/US (0.86 years; P = .003). For recurrences detected by SI, more tumor foci at relapse ( P < .001) and size of the largest focus greater than 2 cm ( P = .02) were associated with inferior OS. However, there was no difference in OS after relapse when recurrence was detected by CT versus CXR/US (5-year OS rate, 65% v 73%; P = .20).

CONCLUSION

In patients with favorable-histology WT, elimination of CT scans from surveillance programs is unlikely to compromise survival but would result in substantial reduction in radiation exposure and health care costs.

High-dose chemotherapy and autologous hematopoietic stem-cell rescue for treatment of relapsed and refractory Wilms tumor: Re-evaluating outcomes

Wilms tumor (WT) treatment regimens are curative for more than 80% of patients, but those with relapsed or refractory disease continue to have poor outcomes. High-dose chemotherapy followed by autologous stem cell rescue is often utilized although outcomes remain variable. We report on HD-ASCR outcomes in 24 patients with relapsed or refractory Wilms tumor. Three-year disease free and overall survival are 46% and 60%, respectively, which is similar to those reported for conventional salvage therapies. These outcomes suggest that conventional salvage therapies should be employed for relapsed and refractory WT rather than HD-ASCR.

Relapse of Wilms' tumour and detection methods: a retrospective analysis of the 2001 Renal Tumour Study Group-International Society of Paediatric Oncology Wilms' tumour protocol database

BACKGROUND

Wilms' tumour is the most common renal cancer in childhood and about 15% of patients will relapse. There is scarce evidence about optimal surveillance schedules and methods for detection of tumour relapse after therapy.

METHODS

The Renal Tumour Study Group-International Society of Paediatric Oncology (RTSG-SIOP) Wilms' tumour 2001 trial and study is an international, multicentre, prospective registration, biological study with an embedded randomised clinical trial for children with renal tumours aged between 6 months and 18 years. The study covers 243 different centres in 27 countries grouped into five consortia. The current protocol of SIOP surveillance for Wilms' tumour recommends that abdominal ultrasound and chest x-ray should be done every 3 months for the first 2 years after treatment and be repeated every 4-6 months in the third and fourth year and annually in the fifth year. In this retrospective cohort study of the protocol database, we analysed data from participating institutions on timing, anatomical site, and mode of detection of all first relapses of Wilms' tumour. The primary outcomes were how relapse of Wilms' tumour was detected (ie, at or between scheduled surveillance and with or without clinical symptoms, scan modality, and physical examination) and to estimate the number of scans needed to capture one subclinical relapse. The RTSG-SIOP study is registered with Eudra-CT, number 2007-004591-39.

FINDINGS

Between June 26, 2001, and May 8, 2015, of 4271 eligible patients in the 2001 RTSG-SIOP Wilms' tumour database, 538 (13%) relapsed. Median follow-up from surgery was 62 months (IQR 32-93). The method used to detect relapse was registered for 410 (76%) of 538 relapses. Planned surveillance imaging captured 289 (70%) of these 410 relapses. The primary imaging modality used to detect relapse was reported for 251 patients, among which relapse was identified by abdominal ultrasound (80 [32%] patients), chest x-ray (78 [31%]), CT scan of the chest (64 [25%]) or abdomen (20 [8%]), and abdominal MRI (nine [4%]). 279 (68%) of 410 relapses were not detectable by physical examination and 261 (64%) patients did not have clinical symptoms at relapse. The estimated number of scans needed to detect one subclinical relapse during the first 2 years after nephrectomy was 112 (95% CI 106-119) and, for 2-5 years after nephrectomy, 500 (416-588).

INTERPRETATION

Planned surveillance imaging captured more than two-thirds of predominantly asymptomatic relapses of Wilms' tumours, with most detected by abdominal ultrasound, chest x-ray, or chest CT scan. Beyond 2 years post-nephrectomy, a substantial number of surveillance scans are needed to capture one relapse, which places a burden on families and health-care systems.

FUNDING

Great Ormond Street Hospital Children's Charity, the European Expert Paediatric Oncology Reference Network for Diagnostics and Treatment, The Danish Childhood Cancer Foundation, Cancer Research UK, the UK National Cancer Research Network and Children's Cancer and Leukaemia Group, Société Française des Cancers de l'Enfant and Association Leon Berard Enfant Cancéreux and Enfant et Santé, Gesellschaft für Pädiatrische Onkologie und Hämatologie and Deutsche Krebshilfe, Grupo Cooperativo Brasileiro para o Tratamento do Tumor de Wilms and Sociedade Brasileira de Oncologia Pediátrica, the Spanish Society of Pediatric Haematology and Oncology and the Spanish Association Against Cancer, and SIOP-Netherlands.

Vincristine, Irinotecan, and Bevacizumab in Relapsed Wilms Tumor With Diffuse Anaplasia

The prognosis of relapsed Wilms tumor (WT) with diffuse anaplasia is dismal, therefore, novel therapeutic strategies need to be explored. We reported on 2 consecutive cases with relapsed anaplastic WT who presented a partial response after 2 courses of vincristine, irinotecan, and bevacizumab association. This regimen may have a role in the treatment of patients with anaplastic advanced WT.

MiR-1180-5p regulates apoptosis of Wilms' tumor by targeting p73

Introduction

Wilms’ tumor (WT), the most common childhood tumor, occurs in sporadic or familial forms. Recent findings reported that abnormal expression in microRNA (miRNA) suggests an important role of miRNAs during WT progress. MiRNAs are endogenous short-chain noncoding RNAs, which have been reported as key biomarkers for detecting tumor onset and progression. However, the functional role of miR-1180 in WT has remained unknown.

Materials and methods

MTT and clonogenic survival assays were used to detect WT cell proliferation. Flow cytometry Annexin V-FITC was used to measure apoptosis. In addition, proteins expressions in the cells were determined by Western blotting.

Results

In the present study, we demonstrated that miR-1180 is upregulated in WT when compared with adjacent tissues by quantitative reverse-transcription polymerase chain reaction. In addition, the inhibition of miR-1180 induced apoptosis in SK-NEP-1 cell line in vitro. Moreover, luciferase reporter assay showed that p73 protein was the target of miR-1180, which was confirmed by the results of Western blotting. Finally, in vivo data indicated that the tumor growth in mice was significantly inhibited by miR-1180 inhibitor.

Conclusion

Our results indicate that miR-1180 might serve as a therapeutic target for future WT therapy.

Irinotecan for relapsed Wilms tumor in pediatric patients: SIOP experience and review of the literature-A report from the SIOP Renal Tumor Study Group

While irinotecan has been studied in various pediatric solid tumors, its potential role in Wilms tumor (WT) is less clear. We evaluated response and outcome of irinotecan-containing regimens in relapsed WT and compared our results to the available literature. Among 14 evaluable patients, one complete response (CR) and two partial responses (PRs) were observed in patients with initial intermediate-risk (CR and PR) and blastemal-type histologies (PR). Two patients were alive at last follow-up showing no evidence of disease. Our results and the reviewed literature suggest some effectiveness of irinotecan in the setting of relapsed WT.

Association between long interspersed nuclear element-1 methylation levels and relapse in Wilms tumors

Background

Wilms tumor (WT) is a curable pediatric renal malignancy, but there is a need for new molecular biomarkers to improve relapse risk-directed therapy. Somatic alterations occur at relatively low frequencies whereas epigenetic changes at 11p15 are the most common aberration. We analyzed long interspersed element-1 (LINE-1) methylation levels in the blastemal component of WT and normal kidney samples to explore their prognostic significance.

Results

WT samples presented a hypomethylated pattern at all five CpG sites compared to matched normal kidney samples; therefore, the averaged methylation levels of the five CpG sites were used for further analyses. WT presented a hypomethylation profile (median 65.0%, 47.4–73.2%) compared to normal kidney samples (median 71.8%, 51.5–77.5%; p < 0.0001). No significant associations were found between LINE-1 methylation levels and clinical–pathological characteristics. We observed that LINE-1 methylation levels were lower in tumor samples from patients with relapse (median methylation 60.5%) compared to patients without relapse (median methylation 66.5%; p = 0.0005), and a receiving operating characteristic curve analysis was applied to verify the ability of LINE-1 methylation levels to discriminate WT samples from these patients. Using a cut-off value of 62.71% for LINE-1 methylation levels, the area under the curve was 0.808, with a sensitivity of 76.5% and a specificity of 83.3%. Having identified differences in LINE-1 methylation between WT samples from patients with and without relapse in this cohort, we evaluated other prognostic factors using a logistic regression model. This analysis showed that in risk stratification, LINE-1 methylation level was an independent variable for relapse risk: the lower the methylation levels, the higher the risk of relapse. The logistic regression model indicated a relapse risk increase of 30% per decreased unit of methylation (odds ratio 1.30; 95% confidence interval 1.07–1.57).

Conclusion

Our results reinforce previous data showing a global hypomethylation profile in WT. LINE-1 methylation levels can be suggested as a marker of relapse after chemotherapy treatment in addition to risk classification, helping to guide new treatment approaches.

Electronic supplementary material

The online version of this article (10.1186/s13148-017-0431-6) contains supplementary material, which is available to authorized users.

Position paper: Rationale for the treatment of Wilms tumour in the UMBRELLA SIOP-RTSG 2016 protocol

The Renal Tumour Study Group of the International Society of Paediatric Oncology (SIOP-RTSG) has developed a new protocol for the diagnosis and treatment of childhood renal tumours, the UMBRELLA SIOP-RTSG 2016 (the UMBRELLA protocol), to continue international collaboration in the treatment of childhood renal tumours. This protocol will support integrated biomarker and imaging research, focussing on assessing the independent prognostic value of genomic changes within the tumour and the volume of the blastemal component that survives preoperative chemotherapy. Treatment guidelines for Wilms tumours in the UMBRELLA protocol include recommendations for localized, metastatic, and bilateral disease, for all age groups, and for relapsed disease. These recommendations have been established by a multidisciplinary panel of leading experts on renal tumours within the SIOP-RTSG. The UMBRELLA protocol should promote international collaboration and research and serve as the SIOP-RTSG best available treatment standard.

Review of phase I and II trials for Wilms' tumour - Can we optimise the search for novel agents?

Survival rates for patients with Wilms' tumour (WT) approximate 90% with refined use of currently available interventions. However, a subgroup of patients, with initial high-risk histopathology or relapsing disease, have a poor prognosis, and it is a challenge to identify and prioritise the development of new innovative approaches for these subgroups. We conducted a systematic literature search for published phase I and II clinical trials that registered patients with WTs and characterised the early phase trial activity, quantified response rates and highlighted avenues for further development. We identified 63 trials (48 phase I, three phase I/II, and 12 phase II trials) enrolling 214 patients with WTs, alongside other malignancies. The number of annually recruited WTs did not change significantly and was less than 20% of the potential candidates. The vast majority of the trials were conducted in North America, and 56 different interventions were investigated, including conventional chemotherapy and biologically targeted therapies. Overall, 33 WTs revealed some degree of tumour control. Of these, five patients demonstrated complete remission (2%), 15 patients partial response (7%) and 13 patients stable disease (6%). None of the included novel biologically targeted therapies emerged as promising interventions, and only conventional chemotherapy was able to induce a complete and partial response. We conclude that early phase trial recruitment of WTs is below expected levels, and the clinical outcome of the included patients is dismal. Improvement of the availability and recruitment to early phase trials for WTs, especially in Europe, is needed.

Recent advances in the management of Wilms' tumor

The objective of this article is to present an overview of recent trends in the management of Wilms’ tumor. With improved survival rates in the past few decades, critical long-term adverse therapy effects (such as renal insufficiency, secondary malignancies, and heart failure) and prevention measures (i.e. nephron-sparing surgery and minimizing the use of radiotherapy) have gained worldwide attention. Specific disease biomarkers that could help stratify high-risk from low-risk patients, and therefore fine-tune management, are in great demand. Ultimately, we aim to enhance clinical outcomes and maintain or improve current survival rates while avoiding undesirable treatment side effects and minimizing the exposure and intensity of chemotherapy and radiotherapy.

Chromosomal anomalies at 1q, 3, 16q, and mutations of SIX1 and DROSHA genes underlie Wilms tumor recurrences

Approximately half of children suffering from recurrent Wilms tumor (WT) develop resistance to salvage therapies. Hence the importance to disclose events driving tumor progression/recurrence. Future therapeutic trials, conducted in the setting of relapsing patients, will need to prioritize targets present in the recurrent lesions. Different studies identified primary tumor-specific signatures associated with poor prognosis. However, given the difficulty in recruiting specimens from recurrent WTs, little work has been done to compare the molecular profile of paired primary/recurrent diseases. We studied the genomic profile of a cohort of eight pairs of primary/recurrent WTs through whole-genome SNP arrays, and investigated known WT-associated genes, including SIX1, SIX2 and micro RNA processor genes, whose mutations have been recently proposed as associated with worse outcome. Through this approach, we sought to uncover anomalies characterizing tumor recurrence, either acquired de novo or already present in the primary disease, and to investigate whether they overlapped with known molecular prognostic signatures.

Among the aberrations that we disclosed as potentially acquired de novo in recurrences, some had been already recognized in primary tumors as associated with a higher risk of relapse. These included allelic imbalances of chromosome 1q and of chromosome 3, and CN losses on chromosome 16q. In addition, we found that SIX1 and DROSHA mutations can be heterogeneous events (both spatially and temporally) within primary tumors, and that their co-occurrence might be positively selected in the progression to recurrent disease. Overall, these results provide new insights into genomic and genetic events underlying WT progression/recurrence.

Paediatric renal tumours: perspectives from the SIOP-RTSG

The >90% rates of overall survival for children with Wilms tumour are remarkable and have been achieved at the same time as reducing treatment for most patients. However, beneath this headline figure, 20% of patients still relapse after first-line therapy and up to 25% of survivors report severe late effects. The aim of the SIOP-RTSG is to improve outcomes and to reduce acute and late treatment toxic effects in all children.

An Unusual Late Recurrence of Wilms Tumor

Wilms tumor is the most common renal tumor in children, and the 5-year survival rate is approximately 85%. The majority of relapses occur in the lung, tumor bed, and liver within 2 years of diagnosis. In this study, we describe an unusual late tumor recurrence that occurred 9.5 years after the primary diagnosis. The patient presented with a slow growing cervical lymphadenopathy. The recurrent tumor showed the same histologic features as the original tumor. The patient was treated with surgery and radiotherapy without chemotherapy. The patient remained disease free 15 months after treatment. The possible effect of treatment and other mechanisms of this late relapse are discussed.

Advances in Wilms Tumor Treatment and Biology: Progress Through International Collaboration

Clinical trials in Wilms tumor (WT) have resulted in overall survival rates of greater than 90%. This achievement is especially remarkable because improvements in disease-specific survival have occurred concurrently with a reduction of therapy for large patient subgroups. However, the outcomes for certain patient subgroups, including those with unfavorable histologic and molecular features, bilateral disease, and recurrent disease, remain well below the benchmark survival rate of 90%. Therapy for WT has been advanced in part by an increasingly complex risk-stratification system based on patient age; tumor stage, histology, and volume; response to chemotherapy; and loss of heterozygosity at chromosomes 1p and 16q. A consequence of this system has been the apportionment of patients into such small subgroups that only collaboration between large international WT study groups will support clinical trials that are sufficiently powered to answer challenging questions that move the field forward. This article gives an overview of the Children's Oncology Group and International Society of Pediatric Oncology approaches to WT and focuses on four subgroups (stage IV, initially inoperable, bilateral, and relapsed WT) for which international collaboration is pressing. In addition, biologic insights resulting from collaborative laboratory research are discussed. A coordinated expansion of international collaboration in both clinical trials and laboratory science will provide real opportunity to improve the treatment and outcomes for children with renal tumors on a global level.

Treatment of relapsed Wilms tumour (WT) patients: experience with topotecan. A report from the SIOP Renal Tumour Study Group (RTSG)

BACKGROUND

Topotecan has been variably incorporated in the treatment of patients with relapsed Wilms tumour (WT) who failed initial treatment with three or more effective drugs. Our objective was to describe outcome and to retrospectively investigate the potential role of topotecan in relapsed WT patients.

METHODS

Children who were treated with topotecan as part of their chemotherapeutic regimens for relapsed WT were identified and included in our retrospective study. Patient charts were reviewed for general patient characteristics, histology and stage at initial diagnosis, number and type of relapse, salvage treatment schedules, toxicity, response to treatment and outcome.

RESULTS

From 2000 to 2012, 30 children (median age at relapse 5.5 years, range 1.6-14.5 years) were identified to have received topotecan as part of their salvage regimens (primary progressive disease n = 3, first, second and third relapse n = 13, 9 and 2 respectively, partial response n = 3). Topotecan was administered as a single agent (12 patients) or in combination with other drugs (18 patients). Sixteen patients had high-risk histology according to the SIOP classification, 15 died within 12 months because of progressive disease. Fourteen patients had SIOP intermediate-risk histology of which four patients displayed objective responses to topotecan. Overall, 6 out of 14 intermediate-risk patients survived (median follow up of 6 years), however, three of whom (stage V) had bilateral nephrectomy after topotecan treatment.

CONCLUSIONS

Topotecan does not seem to show effectiveness in the treatment of relapsed WT patients with initial high-risk histology. In patients with intermediate-risk histology, the role of topotecan might deserve further attention, to prove its efficacy.