Current management of Wilms' tumor in children

RENAL nephrometry scoring system in bilateral Wilms tumor: predictive application

AIM

This study aims to explore the application of RENAL nephrometry scoring system in bilateral Wilms tumor (BWT).

METHODS

A retrospective review of patients with BWT from January 2010 to June 2022 was performed. Each kidney unit of the BWT was evaluated independently and scored according to RENAL nephrometry scoring system by 2 blinded reviewers, and reviewers were blinded to what surgery the patients ultimately had. Discrepancies were evaluated by a third reviewer to reach a consensus. Tumor anatomical characteristics were summarized and compared.

RESULTS

29 patients with 53 kidney units were included in the study. 53 kidney units included 12 (22.6%) low-complexity, 9 (17.0%) intermediate-complexity, and 32 (60.4%) high-complexity. 2 kidney units (3.8%) had tumor thrombus, and 14 (26.4%) had multiple lesions. A total of 42 kidney units (79.2%) underwent initial nephron-sparing surgery (NSS) and 11 (20.8%) underwent radical nephrectomy. Less complexity tumors were observed in the NSS group. Of the 42 kidney units undergoing initial NSS, 26 were performed in vivo and 16 ex vivo via autotransplantation. The latter group featured a higher complexity. During follow-up, 22 patients survived and 7 died, no statistically significant tumor complexity was observed between the two groups.

CONCLUSIONS

The anatomical characteristics of BWT are complex. Despite this study did not indicate that the complexity correlates with prognosis, low-complexity tumors were candidates for NSS, and kidney autotransplantation provided a feasible procedure for high-complexity tumors. A refined system is required due to multiple lesions and tumor thrombus.

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.

Role of Ultrasonography in the Diagnosis of Wilms’ Tumour

Background. Wilms’ tumour or nephroblastoma is the most common renal malignancy encountered in the paediatric population. Imaging findings are of great importance to the surgeon, the oncologist and the radiologist in the diagnosis and the staging and surveillance of this tumour. Material and Methods. This study was carried out as a 10-year retrospective study of patients who were diagnosed with Wilms’ tumour. Results. The study included 12 boys and 11 girls. Ultrasound and computed tomography were performed in all cases. Ultrasonography was found to be superior to the CT examination when approximating the antero-posterior and transverse diameters; the computer-tomographic examination is cited as superior for estimating the invasion of nephroblastomas. Conclusions: Ultrasound has been shown to be effective in detecting the rupture of the renal capsule, tumour calcifications and invasion of the renal vein, pelvis and ureter. However, ultrasound cannot replace CT in the detection of lymphadenopathy and the invasion of adjacent organs.

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.

Wilms’ tumor in low- and middle-income countries: survey of current practices, challenges, and priorities

Purpose

To identify the current practices and priorities in Wilms’ tumor management for surgeons in low- and middle-income countries (LMICs).

Methods

One hundred thirty-seven pediatric surgeons from 44 countries completed surveys on Wilms’ tumor surgical strategy in LMIC. This survey was distributed through the Global Initiative for Children’s Surgery, Pan-African Pediatric Surgical Association, and Latin American Pediatric Surgical Oncology Group.

Results

Ninety-two respondents (67.2%) participated from 19 lower middle-income countries (43.2%). Twenty-one respondents (15.3%) participated from nine lower income countries (20.5%). Nineteen respondents (13.9%) participated from 13 upper middle-income countries (29.5%). Most providers do not obtain biopsy for suspected Wilms’ tumor (79%). Delayed resection after preoperative chemotherapy is the preferred approach (70%), which providers chose due to protocol (45%), to decrease tumor rupture (22%), and to decrease complications (8%). The providers’ goal was to prevent tumor spillage and upstaging (46%) or to prevent bleeding, complication, or other organ resections (21%). Most surgeons believed that upfront resection increased the risk of tumor spillage (72%).

Conclusion

Providers in LMICs prefer delayed resection after preoperative chemotherapy to reduce the incidence of tumor spillage and upstaging of Wilms’ tumor. An evidence-based guideline tailored to the LMIC context can be developed from these findings.

Identification of CDC20 as a Novel Biomarker in Diagnosis and Treatment of Wilms Tumor

Objective: Wilms tumor (WT) is a common malignant solid tumor in children. Many tumor biomarkers have been reported; however, there are poorly targetable molecular mechanisms which have been defined in WT. This study aimed to identify the oncogene in WT and explore the potential mechanisms. Methods: Differentially expressed genes (DEGs) in three independent RNA-seq datasets were downloaded from The Cancer Genome Atlas data portal and the Gene Expression Omnibus database (GSE66405 and GSE73209). The common DEGs were then subjected to Gene Ontology enrichment analysis, protein-protein interaction (PPI) network analysis, and gene set enrichment analysis. The protein expression levels of the hub gene were analyzed by immunohistochemical analysis and Western blotting in a 60 WT sample. The univariate Kaplan-Meier analysis for overall survival was performed, and the log-rank test was utilized. A small interfering RNA targeting cell division cycle 20 (CDC20) was transfected into G401 and SK-NEP-1 cell lines. The Cell Counting Kit-8 assay and wound healing assay were used to observe the changes in cell proliferation and migration after transfection. Flow cytometry was used to detect the effect on the cell cycle. Western blot was conducted to study the changes of related functional proteins. Results: We commonly identified 44 upregulation and 272 downregulation differentially expressed genes in three independent RNA-seq datasets. Gene and pathway enrichment analyses of the regulatory networks involving hub genes suggested that cell cycle changes are crucial in WT. The top 15 highly connected genes were found by PPI network analysis. Furthermore, we demonstrated that one candidate biomarker, CDC20, for the diagnosis of WT was detected, and its high expression predicted poor prognosis of WT patients. Moreover, the area under the curve value obtained by receiver operating characteristic curve analysis from paired WT samples was 0.9181. Finally, we found that the suppression of CDC20 inhibited proliferation and migration and resulted in G2/M phase arrest in WT cells. The mechanism may be involved in increasing the protein level of securin, cyclin B1, and cyclin A Conclusion: Our results suggest that CDC20 could serve as a candidate diagnostic and prognostic biomarker for WT, and suppression of CDC20 may be a potential approach for the prevention and treatment of WT.

Childhood Cancer: Occurrence, Treatment and Risk of Second Primary Malignancies

Cancer represents the leading cause of disease-related death and treatment-associated morbidity in children with an increasing trend in recent decades worldwide. Nevertheless, the 5-year survival of childhood cancer patients has been raised impressively to more than 80% during the past decades, primarily attributed to improved diagnostic technologies and multiagent cytotoxic regimens. This strong benefit of more efficient tumor control and prolonged survival is compromised by an increased risk of adverse and fatal late sequelae. Long-term survivors of pediatric tumors are at the utmost risk for non-carcinogenic late effects such as cardiomyopathies, neurotoxicity, or pneumopathies, as well as the development of secondary primary malignancies as the most detrimental consequence of genotoxic chemo- and radiotherapy. Promising approaches to reducing the risk of adverse late effects in childhood cancer survivors include high precision irradiation techniques like proton radiotherapy or non-genotoxic targeted therapies and immune-based treatments. However, to date, these therapies are rarely used to treat pediatric cancer patients and survival rates, as well as incidences of late effects, have changed little over the past two decades in this population. Here we provide an overview of the epidemiology and etiology of childhood cancers, current developments for their treatment, and therapy-related adverse late health consequences with a special focus on second primary malignancies.

Comprehensive Analysis of a Long Noncoding RNA-Associated Competing Endogenous RNA Network in Wilms Tumor

Long noncoding RNA (lncRNA) plays crucial roles in various biological processes of different cancers, especially acting as a competing endogenous RNA (ceRNA). However, the role of lncRNA-mediated ceRNA in Wilms tumor (WT), which is the most common malignant kidney cancer in children, remains unknown. In present study, RNA sequence profiles and clinical data of 125 patients with WT consisting of 119 tumor and 6 normal tissues from Therapeutically Applicable Research To Generate Effective Treatments database were analyzed. A total of 1833 lncRNAs, 156 microRNAs (miRNAs), and 3443 messenger RNAs (mRNAs) were identified as differentially expressed (DE) using "DESeq2" package. The lncRNA-miRNA-mRNA ceRNA regulatory network involving 748 DElncRNAs, 33 DEmiRNAs, and 189 DEmRNAs was constructed based on miRcode, Targetscan, miRTarBase, and miRDB database. Gene Ontology term and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed that DEmRNAs were mainly enriched in cell proliferation-related processes and tumor-related pathways, respectively, and 13 hub genes were identified by a protein-protein interaction network. Survival analysis detected 48 lncRNAs, 7 miRNAs, and 16 mRNAs to have significant impact on the overall survival of patients with WT. Additionally, we found that 6 DElncRNAs with potential prognostic value were correlated with tumor stage (DENND5B-AS1) and histologic classification (TMPO-AS1, RP3-523K23.2, RP11-598F7.3, LAMP5-AS1, and AC013275.2) of patients with WT. Our research provides a great insight into understanding the molecular mechanism underlying occurrence and progression of WT, as well as the potential to develop targeted therapies and prognostic biomarkers.

METTL3 polymorphisms and Wilms tumor susceptibility in Chinese children: A five-center case-control study

BACKGROUND

Wilms tumor is a common pediatric tumor worldwide. Methyltransferase like 3 (METTL3) is a core gene of the N⁶ -methyladenosine (m⁶ A) modification that widely affects the transcription of tumor-related genes in eukaryotes. METTL3 has been extensively investigated in various tumors but not Wilms tumor.

METHODS

We describe a five-center case-control study with 414 patients and 1199 controls aiming to explore the associations between METTL3 polymorphisms (rs1061026 T>G, rs1061027 C>A, rs1139130 A>G and rs1263801 G>C) and Wilms tumor susceptibility. A TaqMan real-time polymerase chain reaction was performed for genotyping. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported as evaluation indicators to determine any associations.

RESULTS

Referring to the preliminary analysis results, protective genotypes were identified as rs1061026 TG/GG, rs1061027 CA/AA, rs1139130 GG and rs1263801 GC/CC. The children with three protective genotypes were less likely to develop Wilms tumor than children without protective genotypes (adjusted OR = 0.68, 95% CI = 0.46-0.999, p = 0.0496). Similarly, stratified analysis of the subgroup aged > 18 months, carrying 3 or 4 protective genotypes, was a protective factor for Wilms tumor compared to carrying 0-2 protective genotypes (adjusted OR = 0.59 95% CI = 0.39-0.91, p = 0.016). However, we did not observe any other significant results.

CONCLUSIONS

The combined effect of METTL3 polymorphisms reduce Wilms tumor susceptibility in Chinese children. This conclusion requires further verification.

Minimally invasive surgery for pediatric renal tumors: A systematic review by the APSA Cancer Committee

Minimally invasive nephrectomy is performed routinely for adult renal tumors and for many benign pediatric conditions. Although open radical nephroureterectomy remains the standard of care for Wilms tumor and most pediatric renal malignancies, there are an increasing number of reports of minimally invasive surgery (MIS) for those operations as well. The APSA Cancer Committee performed a systematic review to better understand the risks and benefits of MIS in pediatric patients with renal tumors.

METHODS

The search focused on MIS for renal tumors in children and followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) checklist. The initial database search identified 491 published articles, and after progressive review of abstracts and full-length articles, 19 were included in this review.

RESULTS

There were two direct comparison studies where open surgery and MIS were compared. The remaining studies reported only on minimally invasive nephrectomy. Across all studies, there were a total of 151 patients, 126 of which had Wilms tumor and 10 patients had RCC. 104 patients had MIS, with 47 patients having open surgery. In the two studies in which open surgery and MIS were directly compared, more lymph nodes were harvested during open surgery (median = 2 (MIS) vs 5 (open); mean = 2.47 (MIS) vs 3.8 (open)). Many noncomparison studies reported the harvest of 2 of fewer lymph nodes for Wilms tumor. Several MIS patients were also noted to have intraoperative spill or positive margins. Survival between groups was similar.

CONCLUSIONS

There is a lack of evidence to support MIS for pediatric renal tumors. This review demonstrates that lymph node harvest has been inadequate for MIS pediatric nephrectomy and there appears to be an increased risk for intraoperative spill. Survival data are similar between groups, but follow-up times were inconsistent and patient selection was clearly biased, with only small tumors being selected for MIS.

TYPE OF STUDY

Review article.

LEVEL OF EVIDENCE

III.

The Effects of Genetic and Epigenetic Alterations of BARD1 on the Development of Non-Breast and Non-Gynecological Cancers

Breast Cancer 1 (BRCA1) gene is a well-characterized tumor suppressor gene, mutations of which are primarily found in women with breast and ovarian cancers. BRCA1-associated RING domain 1 (BARD1) gene has also been identified as an important tumor suppressor gene in breast, ovarian, and uterine cancers. Underscoring the functional significance of the BRCA1 and BARD1 interactions, prevalent mutations in the BRCA1 gene are found in its RING domain, through which it binds the RING domain of BARD1. BARD1-BRCA1 heterodimer plays a crucial role in a variety of DNA damage response (DDR) pathways, including DNA damage checkpoint and homologous recombination (HR). However, many mutations in both BARD1 and BRCA1 also exist in other domains that significantly affect their biological functions. Intriguingly, recent genome-wide studies have identified various single nucleotide polymorphisms (SNPs), genetic alterations, and epigenetic modifications in or near the BARD1 gene that manifested profound effects on tumorigenesis in a variety of non-breast and non-gynecological cancers. In this review, we will briefly discuss the molecular functions of BARD1, including its BRCA1-dependent as well as BRCA1-independent functions. We will then focus on evaluating the common BARD1 related SNPs as well as genetic and epigenetic changes that occur in the non-BRCA1-dominant cancers, including neuroblastoma, lung, and gastrointestinal cancers. Furthermore, the pro- and anti-tumorigenic functions of different SNPs and BARD1 variants will also be discussed.

MYC gene associated polymorphisms and Wilms tumor risk in Chinese children: a four-center case-control study

BACKGROUND

Wilms tumor (WT) is a common embryonal malignancy in the kidney, ranking fourth in childhood cancer worldwide. MYC, a critical proto-oncogene, plays an important role in tumorigenesis. Single nucleotide polymorphisms in the MYC gene may lead to the deregulation of MYC proto-oncogene protein and thereby promote the initiation and development of tumors.

METHODS

Here, we assessed the association between MYC gene associated polymorphisms and WT susceptibility by performing a case-control study with 355 cases and 1070 controls. Two MYC gene associated polymorphisms (rs4645943 C > T, rs2070583 A > G) were genotyped by TaqMan technique. Odds ratios (ORs) and 95% confidence intervals (CIs) were used for evaluating the association between these two polymorphisms and WT susceptibility.

RESULTS

No significant association was detected between the selected polymorphisms and WT risk in the overall analysis as well as stratification analysis.

CONCLUSIONS

These results indicate that neither of two selected MYC gene associated polymorphisms might affect WT susceptibility in the Chinese population. Large well-designed studies with diverse ethnicities are warranted to verify these results.

National Survey on the Management of Wilms Tumor

This study aims to investigate the management of Wilms tumor by the Egyptian pediatric surgical association (EPSA) consultants. After approval of the EPSA executive board, a questionnaire was distributed individually to all consultants attending the general assembly of EPSA 2017 annual congress. Of 88 consultants, responses were received from 61. Palpable abdominal mass was indicated by 72.13% of respondents as the commonest presenting symptom. Concerning the imaging requested, computed tomography was reported by 80.33%. Approximately 62.30% of respondents perform 1 to 3 cases annually. Regarding timing of surgery, upfront resection was the most frequently reported by 62.30%. A total of 77.05% perform lymph node sampling during surgeries. Nephron-sparing surgery was adopted by only 26.23%, whereas none of the respondents reported the use of minimally invasive surgery for management. Overall, 93.44% of surgeons ask for a visit every 3 months in the first year postoperatively. Upfront nephrectomy is the commonest procedure for Wilms tumor in the current practice of EPSA consultants, whereas there is consensus against minimally invasive surgery. Surgical guidelines for nephron-sparing surgery are still incomplete and need to be tabulated. This study urges for a nationwide retrospective analysis to establish a uniform protocol with international reference to be adopted in Egypt.

Clinical outcomes of children with Wilms tumor treated on a SIOP WT 2001 protocol in a tertiary care hospital in south India

INTRODUCTION

Wilms tumor is the most common pediatric renal malignancy. While developed countries have had excellent survival, it remains poorer by comparison in developing countries. The aim was to analyze the clinical outcome of children with Wilms tumor managed in a developing country from 2004 to 2014 by the SIOP WT 2001 protocol.

METHODS

Fifty-nine children with Wilms tumor managed by a SIOP WT 2001 regimen from 2004 to 2014 were analyzed.

RESULTS

The median age at presentation was 36 months, and 59% were boys. The average size of the tumor at presentation was 523 mL. Inferior vena cava thrombus was present in 11, distant metastases in 18, and bilateral tumors in six. Preoperative chemotherapy was given to all children after a diagnostic core needle biopsy. Preoperative chemotherapy reduced the tumor size to a mean of 208 mL and resolved venacaval thrombus in eight. Fifty-five children underwent definitive surgery while two children died during preoperative chemotherapy and two remained inoperable. All surviving children received adjuvant chemotherapy with 17 receiving radiotherapy as well. The overall survival (OS) was 80% and the event-free survival (EFS) was 73% after a mean follow up of 42 months after completion of therapy.

DISCUSSION

The tumor volumes at presentation and the incidence of venous tumor thrombosis in our cohort were much higher than those reported from developed countries. The incidence of metastatic disease at diagnosis (30.5%) was significantly higher than the 10-12% reported in Western data, but similar to that reported from various developing countries (14.1-31%). The OS in our cohort was 80% and the EFS was 73% with there being no events after 28 months. Although the survival rate for localized disease is similar to that in developed countries, the OS for metastatic disease was significantly less (50% vs. 75%). We also found that using an upfront posterior flank core biopsy was safe and beneficial for differentiating Wilms tumor from other pediatric renal tumors that are less chemosensitive.

CONCLUSION

In a resource-restricted environment such as ours, the SIOP WT 2001 protocol has been found to show excellent results.

Evaluation of effect of preoperative chemotherapy on Wilms' tumor histopathology

PURPOSE

To evaluate usefulness of cutting needle biopsy (CNB) to recognize pediatric renal tumors and to predict the evolution of histology during preoperative chemotherapy of Wilms tumors.

METHODS

Ninety pediatric patients were operated for renal tumors at our institution in 1988-2015. We included all 64 patients who had undergone CNB at diagnosis and whose CNB and nephrectomy samples were available for re-evaluation.

RESULTS

The CNB was diagnostic in all 59 Wilms tumors but only in two out of five non-Wilms tumors. Anaplasia was missed by CNB in one of three with diffuse anaplasia in nephrectomy specimens. In Wilms tumors the proportions of the blastemal, stromal and epithelial components were 55% (IQR 25-85), 28% (IQR 10-58) and 2% (IQR 0-10) in CNB samples and 5% (IQR 0-64), 15% (IQR 0-50) and 15% (IQR 0-44) in the nephrectomy specimens (p-values 0.002, 0.599 and 0.005 respectively). The degree of tumor necrosis was in median 80% (IQR 21-97), after preoperative chemotherapy. The degree of tumor necrosis after chemotherapy had a positive correlation with the proportion of blastemal component (p=0.008) and a negative correlation with proportion of epithelial component in pre-chemotherapy CNB samples (p<0.001).

CONCLUSIONS

Wilms tumors are usually recognizable unlike non-Wilms tumors in CNB at diagnosis. In Wilms tumors, high blastemal cell content is associated with significant tumor necrosis during pre-operative chemotherapy. Our results do not support routine use of CNB in diagnosis of renal tumors.

TYPE OF STUDY

Retrospective review.

LEVEL OF EVIDENCE

Level III.

Base Excision Repair Gene Polymorphisms and Wilms Tumor Susceptibility

Base excision repair (BER) is the main mechanism to repair endogenous DNA lesions caused by reactive oxygen species. BER deficiency is linked with cancer susceptibility and premature aging. Single nucleotide polymorphisms (SNPs) within BER genes have been implicated in various human malignancies. Nevertheless, a comprehensive investigation of their association with Wilms tumor susceptibility is lacking. In this study, 145 cases and 531 sex and age-matched healthy controls were recruited. We systematically genotyped 18 potentially functional SNPs in six core BER pathway genes, using a candidate SNP approach. Logistic regression was employed to evaluate odds ratio (OR) and 95% confidence interval (CI) adjusted for age and gender. Several SNPs showed protective effects against Wilms tumor. Significant associations with Wilms tumor susceptibility were shown for hOGG1 rs1052133 (dominant: adjusted OR = 0.66, 95% CI = 0.45-0.96, P = .030), FEN1 rs174538 (dominant: adjusted OR = 0.66, 95% CI = 0.45-0.95, P = .027; recessive: adjusted OR = 0.54, 95% CI = 0.32-0.93 P = .027), and FEN1 rs4246215 (dominant: adjusted OR = 0.55, 95% CI = 0.38-0.80, P = .002) polymorphisms. Stratified analysis was performed by age, gender, and clinical stage. Moreover, there was evidence of functional implication of these significant SNPs suggested by online expression quantitative trait locus (eQTL) analysis. Our findings indicate that common SNPs in BER genes modify susceptibility to Wilms tumor.

Nephrectomy in children with wilms' tumor: 15 years of experience with "Tumor Delivery Technique"

BACKGROUND

The contemporary surgical approach to Wilms' tumors follows that used in adults with renal cell carcinomas, namely, early occlusion of the renal vessels and then removal of the kidney as an intact mass. For years, the surgical approach at our institution has been different, starting with blunt separation of the kidney from the surrounding tissues, followed by its delivery outside the abdominal cavity while it is only attached to the major blood vessels which are subsequently ligated. We aimed to present this "tumor delivery technique" and evaluate its outcomes.

MATERIALS AND METHODS

We retrospectively reviewed medical records of children who underwent nephrectomy for Wilms' tumor using "tumor delivery technique." All procedures were performed by the same team, according to the same surgical principles.

RESULTS

Between 2000 and 2015, 36 children were operated. Median age was 31 months (interquartile range [IQR]: 6-45 mo), and median maximal tumor diameter was 10 cm (IQR: 8-13.9 cm). Tumors were located to the right side in 47%, left side in 42%, and bilateral in 11%. Twelve children have received preoperative neoadjuvant chemotherapy. Capsular disruption and tumor spillage were documented in 4 cases (11%).

CONCLUSIONS

"Tumor delivery technique" is an easy and safe approach which might reduce the overall complication rates and the incidence of intraoperative tumor spillage.

Pediatric oncologic endosurgery

Despite increasing popularity of minimal-invasive techniques in the pediatric population, their use in diagnosis and management of pediatric malignancy is still debated. Moreover, there is limited evidence to clarify this controversy due to low incidence of each individual type of pediatric tumor, huge diversity of the disease entity, heterogeneity of surgical technique, and lack of well-designed studies on pediatric oncologic minimal-invasive surgery. However, a rapid development of medical instruments and technologies accelerated the current trend toward less invasive surgery, including oncologic endosurgery. The aim of this article is to review current literatures about the application of the minimal-invasive approach for pediatric tumors and to give an overview of the current status, indications, individual techniques, and future perspectives.

BARD1 Gene Polymorphisms Confer Nephroblastoma Susceptibility

BRCA1-associated RING domain protein 1 (BARD1) is a tumor suppressor, which forms a heterodimer with BRCA1. Three BARD1 gene polymorphisms (rs7585356 G>A, rs6435862 T>G and rs3768716 A>G) were initially identified as high-risk neuroblastoma susceptibility loci by a previous GWAS. Because of the general tumor-suppressing function of BARD1, we hypothesized that these BARD1 gene polymorphisms might modify the susceptibility to nephroblastoma. We genotyped these polymorphisms in 145 cases and 531 controls using Taqman methods. Out of three polymorphisms, only the rs7585356 G>A polymorphism was significantly associated with increased susceptibility to nephroblastoma [AA vs. GG: adjusted odds ratio (OR)=1.78, 95% confidence interval (CI)=1.01-3.12]. Combined analysis of three polymorphisms indicated that subjects with 3 risk genotypes exhibited significantly elevated nephroblastoma risk, when compared with subjects with 0-2 risk genotypes (adjusted OR=1.72, 95% CI=1.02-2.89). Stratified analysis revealed that in term of clinical stage, rs7585356 AA carriers were associated with increased risk of developing clinical stage I+II nephroblastoma. The presence of three risk genotypes was significantly associated with nephroblastoma risk in females and clinical stage I+II nephroblastoma. Our results suggested that BARD1 rs7585356 G>A may be associated with nephroblastoma risk.

Predictive factor for intraoperative tumor rupture of Wilms tumor

PURPOSE

For Wilms tumor, intraoperative tumor rupture with wide tumor spillage during surgical manipulation raises the classification to stage 3. Then, postoperative chemotherapy must be more intensive, and abdominal radiotherapy is added. Therefore, intraoperative tumor rupture should be avoided if possible. However, predictive factors for intraoperative tumor rupture have not been sufficiently described. Here we examined the risk factors for intraoperative tumor rupture.

METHODS

Patients with Wilms tumor who underwent treatment according to the National Wilms Tumor Study or the Japanese Wilms Tumor Study protocol at our institution were reviewed retrospectively. Collected cases were categorized into two groups: the ruptured group and the non-ruptured group. Risk factors for intraoperative tumor rupture, including the ratio of the tumor area to the abdominal area in a preoperative single horizontal computed tomography slice (T/A ratio), were investigated in both groups.

RESULTS

The two groups were not different in age, body weight, tumor laterality, sex, or histological distribution. The T/A ratio in the ruptured group was significantly higher than that in the non-ruptured group. Receiver operating characteristic curve analysis identified a discriminative value for a T/A ratio >0.5.

CONCLUSION

The T/A ratio can be a predictive factor for intraoperative tumor rupture of Wilms tumor.

Minimally invasive surgery in management of renal tumours in children

Minimally invasive surgery (MIS) in the management of malignant and benign renal tumours in children is gradually becoming more common. Experience is limited and restricted to case reports, retrospective chart reviews and a few cohort studies. There are currently no randomized controlled trials or controlled clinical trials comparing the laparoscopic and open surgical approach for the management of renal tumours in children. MIS may offer the same oncologic outcome in malignant renal tumours whilst providing the advantages associated with MIS in correctly selected cases. The technique for tumour resection has been shown to be feasible in regards to the recommended oncologic principles, although lymph node sampling can be inadequate in some cases. Preliminary reports do not show an increased risk of tumour rupture or inferior oncologic outcomes after MIS. However, the sample size remains small and duration of follow-up inadequate to draw any firm conclusions. Implementation of MIS is lacking in the protocols of the major study groups, and standardized recommendations for the indications and contra-indications remain undefined. The objective of this article is to present a review of the literature on the role of MIS in the management of renal tumours in children, with the main focus on Wilms' tumour (WT). Further studies on MIS in renal tumours are required to evaluate the incidence of oncological complications such as complete tumour resection and intra-operative tumour spillage. A long-term follow-up of patients managed by MIS is essential to compare recurrence rates and overall survival rates.

Renal Late Effects After the Treatment of Unilateral Nonsyndromic Wilms Tumor

Wilms tumor is the most common renal malignancy of childhood. Because of the improvement in prognosis and the increase in survival rates, long-term consequences of the treatment for Wilms tumor are of greater concern. We investigated late renal effects of the treatment on 50 survivors of nonsyndromic unilateral Wilms tumor. After the second year since the cessation of treatment, the glomerular filtration rate (GFR), urinary protein excretion, urinary β2 microglobulin levels, and blood pressure as well as the general health status were assessed. Results were analyzed for correlation with clinical variables, chemotherapy, and radiotherapy as possible risk factors. At a median follow-up time of 8.8 years (mean=10.9; range, 2.3 to 35.4 y), none of the patients developed end-stage renal disease. Compensatory hypertrophy was observed in 68% of the cases. The median maximum bipolar length was significantly higher in patients diagnosed after the age of 36 months. Eleven (22%) and 2 (4%) of the 50 patients were hypertensive at the time of the diagnosis and the study, respectively. Similarly, median GFR values were significantly lower at the time of diagnosis, although at the time of the study, all patients had normal GFR values. With longer follow-up intervals, especially after 10 years, a significant decreasing trend in the GFR was observed (P=0.002).

[Surgical concepts in the treatment of Wilms tumor: An update]

BACKGROUND

Treatment results of Wilms tumors have been impressively improved over the past 50 years resulting in a stage-independent overall survival of greater than 90%. However, unsatisfying treatment results still remain in children with high-risk tumors and tumor relapses.

MATERIALS AND METHODS

This review highlights the current concepts of Wilms tumor surgery as a cornerstone of the treatment strategy for this malignancy. A selective literature review focusing on the past 5 years served as the basis for this article.

RESULTS

Nephron-sparing surgery is associated with an analogue outcome compared to tumor nephrectomy in unilateral Wilms tumors. The surgical panel of the International Society of Pediatric Oncology (SIOP) group has recently introduced a novel nomenclature for organ-preserving resection procedures in order to facilitate a prospective comparison of data. The minimally invasive approach represents an alternative technique with adequate outcome. In bilateral disease, nephron-sparing procedures are gold standard. Complete resection of lung and liver metastases has a significant impact on patients' survival.

CONCLUSIONS

Surgical guidelines for nephron-sparing surgery and minimally invasive tumor nephrectomy need to be established and implemented within newly formulated treatment protocols of the different national and international treatment trials. Risk stratification of patients needs to be more individualized with the aim of reducing late effects while at least maintaining the same survival rates. The unsatisfying treatment results of tumor relapses-associated with low patient numbers within the different trials-emphasize the need for international collaboration.

Management of bilateral Wilms tumor over three decades: The perspective of a single center

INTRODUCTION

Outcomes of Wilms tumor improved in last 50 years and excellent survival rates can be achieved especially in case of non-metastatic disease and favorable histology. Nevertheless, bilateral cases still stand as a therapeutic challenge. Prognosis of bilateral Wilms tumor (BWT) is not as good as the unilateral tumors of similar stage and histology in terms of survival and renal function.

OBJECTIVE

Management of BWT is constantly evolving and still stands as a therapeutic challenge. This study is designed to review and share our experiences on this topic from a surgical standpoint.

STUDY DESIGN

The records of patients treated in our clinic between 1980 and 2013 according to Turkish Pediatric Group of Oncology protocol were analyzed retrospectively and clinical data, surgical details, pathology results, long term outcomes were analyzed.

RESULTS

Thirteen girls and 7 boys with a mean age of 2,5 years were treated. There were 2 patients with Wilms tumor-Aniridia-Growth Retardation complex and one with isolated hemihypertrophy. Metastasis were detected in lungs of 4 patients; liver of 2 and in the cranium of one. All patients except one with the presumptive diagnosis of unilateral Wilms tumor were given preoperative chemotherapy. To sum up; 19 nephroureterectomies, 8 partial nephrectomies and 13 enucleations were performed to 36 kidneys without any major early or late postoperative complications. Pathologic results revealed positive surgical margins in 2 lesions with enucleation and in 2 with partial nephrectomies and anaplasia in 4 patients. Two patients were not operated due to parental disapproval. Two patients had the need of dialysis; one was anephric and the others' renal functions recovered over a year. Seven patients received radiotherapy for pulmonary metastasis, positive surgical margins or local recurrences. Overall, 13 patients survived and 7 died due to metastasis, recurrences, and complication of dialysis and refusal of surgical treatment. Survival among all patients was 65% and 72.2% among operated ones. Of the 7 patients with the partial nephrectomy, 2 died and 5 survived. Among enucleation group, 8 out of 10 survived and 2 died. Survival was slightly higher among enucleation group (80% vs 71.4%). Median time of follow-up for survivors of disease is 5.8 years (min: 6 months and max: 14 years).

DISCUSSION

Outcomes of BWT management have changed dramatically during the last few decades from only survival, to a long life expectancy without the need of renal replacement therapy owing to improvements in treatment options. We argue that positive surgical margins do not necessarily lead to local recurrence. For this reason it may be wiser to favor on more nephron sparing surgery than to achieve negative surgical margins. Adjuvant chemotherapy and radiotherapy may be adequate to prevent local recurrence. Also, survival did not differ significantly between different ways of nephron sparing surgeries, so it may be wiser to choose enucleation over partial nephrectomy which preserves more nephrons. Nephron-sparing surgery should have utmost importance despite the risk of positive margins. On the other hand, there is not enough data to interpret if positive surgical margins have role on distant metastases or not. Presence of metastasis and recurrence seems to be an important determinant of prognosis given the fact that none of the survivors had any metastasis or recurrence.

CONCLUSION

Nephron preservation should be the aim while taking positive surgical margin risk on nephron sparing surgery side relying on postoperative chemotherapy and carefully planned radiotherapy to avoid recurrence. However, there is significant diversity on the management BWT in different centers and a certain validated guideline or protocol to provide the optimal treatment is still lacking.

The role of minimally invasive surgery in pediatric solid tumors

During recent years, minimally invasive surgery (MIS) has become the standard approach for various operations in infants and children. MIS in pediatric thoracic and abdominal tumors is a controversial approach in the surgical management of childhood cancer. Meanwhile, more and more oncological biopsies and resections are being performed laparoscopically or thoracoscopically. Despite its increasing role in pediatric tumor surgery, the different national and international multicenter trial groups have not yet implemented MIS within guidelines and recommendations in most of the current treatment protocols. An increasing number of retrospective reports describes a potential role of MIS in the management of different pediatric oncological entities. Over the time, there has been a diverse development of this approach with regard to the different neoplasms. Nevertheless, there is a lack of prospective randomized trails assessing MIS. This still represents a requirement for evidence-based medicine and judging the advantages and disadvantages of this approach. The purpose of this state-of-the-art article is to review the current literature to describe the application of MIS in pediatric solid tumors.

[Tumor size and prognosis in patients with Wilms tumor]

OBJECTIVE

Investigate the relationship of the tumor volume after preoperative chemotherapy (TVAPQ) and before preoperative chemotherapy (TVBPQ) with overall survival at two and at five years, and lifetime.

METHODS

Our sample consisted of consecutive patients evaluated in the period from 1989 to 2009 in an Onco-Hematology Service. Clinical, histological and volumetric data were collected from the medical records. For analysis, chi-square, Kaplan-Meier, log-rank and Cox regression tests were used.

RESULTS

The sample consisted of 32 patients, 53.1% were male with a median age at diagnosis of 43 months. There was a significant association between TVAPQ >500 mL and the difference between the TVBPQ and TVAPQ (p=0.015) and histologic types of risk (p=0.008). It was also verified an association between the difference between the TVBPQ and TVAPQ and the predominant stromal tumor (p=0.037). When assessing the TVAPQ of all patients, without a cutoff, there was an association of the variable with lifetime (p=0.013), i.e., for each increase of 10 mL in TVAPQ there was an average increase of 2% in the risk of death.

CONCLUSIONS

Although our results indicate that the TVAPQ could be considered alone as a predictor of poor prognosis regardless of the cutoff suggested in the literature, more studies are needed to replace the histology and staging by tumor size as best prognostic variable.

Pathological Features of the Unilateral Favorable Histology Nephroblastoma with Relapse

PURPOSE

To evaluate the pathological features of the primary lesion in patients with relapse of unilateral favorable histology nephroblastoma.

MATERIAL AND METHODS

Fifty-eight patients with unilateral favorable histology nephroblastoma who underwent initial nephrectomy before chemotherapy were categorized into one of two groups: the nonrelapsed group (n = 52) and the relapsed group (n = 6). The histological subtypes of both groups and pathological features of the relapsed group were re-evaluated retrospectively.

RESULTS

The histological subtypes of all relapsed cases were classified as blastemal predominant. In three of six cases with relapse, sheets of spindle-shaped blastemal cells that were histologically reminiscent of synovial sarcoma were predominant (massive sarcomatoid pattern).

CONCLUSIONS

The histological blastemal predominant subtype of nephroblastoma is a strong indicator of relapse. In particular, the blastemal predominant subtype with massive sarcomatoid pattern may have a higher risk of relapse.

Somatic mutations in DROSHA and DICER1 impair microRNA biogenesis through distinct mechanisms in Wilms tumours

Wilms tumour is the most common childhood kidney cancer. Here we report the whole-exome sequencing of 44 Wilms tumours, identifying missense mutations in the microRNA (miRNA)-processing enzymes DROSHA and DICER1, and novel mutations in MYCN, SMARCA4 and ARID1A. Examination of tumour miRNA expression, in vitro processing assays and genomic editing in human cells demonstrates that DICER1 and DROSHA mutations influence miRNA processing through distinct mechanisms. DICER1 RNase IIIB mutations preferentially impair processing of miRNAs deriving from the 5′-arm of pre-miRNA hairpins, while DROSHA RNase IIIB mutations globally inhibit miRNA biogenesis through a dominant-negative mechanism. Both DROSHA and DICER1 mutations impair expression of tumour-suppressing miRNAs, including the let-7 family, important regulators of MYCN, LIN28 and other Wilms tumour oncogenes. These results provide new insights into the mechanisms through which mutations in miRNA biogenesis components reprogramme miRNA expression in human cancer and suggest that these defects define a distinct subclass of Wilms tumours.

Wilms tumour is a common childhood cancer. Here, the authors use whole-exome sequencing in 44 Wilms tumours to characterize their mutational landscape and show that DICER1 and DROSHA mutations can suppress the biogenesis of tumour-suppressing microRNAs.

Wilms' tumor: a 24-year retrospective study from a single center

Medical records of 71 children with Wilms' tumor at Sisli Etfal Education and Research Hospital between 1990 and 2014 were reviewed. Mean age at diagnosis was 3.11 years (2 days-7 years). Male to female ratio was M/F = 6/10. The incidence of associated anomaly was 16.9%. Clinical manifestations included abdominal mass (89%), hematuria (30%), hypertansion (25%), abdominal pain (15%), fever (5%), restlessness (2%), weight loss (2%), varicocele (1%). Ultrasound (USG) was the most often initial study in a child presenting with abdominal mass. Doppler USG was also made to evaluate the inferior vena cava (IVC) for the presence of tumor extension in children with renal mass. The left kidney was affected in 33 patients (46.5%), the right was affected in 31 patients (43.7%). Two patients was extrarenal (2.8%). And 5 patients (7.04%) were bilateral on the presentation. Preoperative chemotheraphy was done in 14 cases. In 63 patients with unilateral Wilm tm, unilateral radical nefrectomy is performed. In one patient with solitary kidney, nephron sparing surgery (NSS) is performed. In 3 patients with bilateral tm NSS is performed and in 2 patients with bilateral Wilms' tm NSS is performed in one side and nefrectomy on the other side. Out of 71 Wilms tumor (WT) patients, 17 of them has been out of our follow. And 4 of them are died. Ten of them has metastases. Forty children are under follow with no metastases. Patients with WT needs a multimodal, multidisiplinary treatment with the cooperation of pediatric oncologist and pediatric surgeon and needs close follow-up.

Comparison between laparoscopic and open radical nephrectomy for the treatment of primary renal tumors in children: single-center experience over a 5-year period

OBJECTIVES

To compare the outcomes of laparoscopic nephrectomy (LN) with open radical nephrectomy (ORN) in the management of consecutive pediatric neoplasms.

PATIENTS AND METHODS

Retrospective cohort study of consecutive children treated for primary renal tumors between 2006 and 2011, segregated based on surgical modality (LN/ORN). Pre-, intra- and postoperative data and outcomes were collected.

RESULTS

Demographics from the 45 patients (13 LN, 32 ORN) were similar, and tumors in the LN group were smaller [6.59 ± 1.8 cm vs. 10.99 ± 2.99 cm ORN (p < 0.05)]. Six patients had preoperative chemotherapy (two LN, four ORN). No tumor ruptures occurred with either technique. Wilms tumor (seven LN, 24 ORN) was the most common diagnosis, followed by renal cell carcinoma (four LN, four ORN). Procedure length was similar between groups (282 ± 79 LN, 263 ± 81 min ORN). Mean length of stay was significantly shorter for LN (2.9 vs. 5.9 days; p = 0.002). Postoperative narcotic requirements and use of nasogastric tube were higher in the ORN group. After a median follow-up of 18 (LN) and 33 months (ORN), 1 and 4 recurrences occurred, respectively.

CONCLUSIONS

LN is an attractive alternative to open surgery in carefully selected cases of pediatric renal tumors. Procedure length and incidence of intra-operative rupture were not increased, while post-operative recovery and hospital stay were shorter for LN. Longer follow-up is mandatory to confirm comparable oncological outcomes to ORN.

Wilms' tumor: biology, diagnosis and treatment

Wilms' tumor is the commonest renal tumor of childhood affecting one in 10,000 children. It is also one of the successes of paediatric oncology with long term survival above 90% for localised disease and 75% for metastatic disease. Successful management of Wilms' tumor necessitates meticulous attention to correct staging of the tumor and a collaborative effort between paediatric oncologists, specialist surgeons, radiologists, pathologists, and radiation oncologists. Although current treatment protocols are based on risk assignment to minimise toxicity for low risk patients and improve outcomes for those with high risk disease, challenges remain in identifying novel molecular, histological and clinical risk factors for stratification of treatment intensity. Knowledge about Wilms' tumor biology and treatment is evolving rapidly and remains a paradigm for multimodal malignancy treatment. Future efforts will focus on the use of biomarkers to improve risk stratification and the introduction of newer molecularly targeted therapies that will minimise toxicity and improve the outcomes for patients with unfavourable histology and recurrent disease. The aim of this article is to summarise advances in our understanding of the biology of Wilms' tumor and to describe the current approaches to clinical management of patients.

Pediatric genitourinary oncology

Tumors of the kidney, bladder, prostate, testis, and adrenal represent a large part of the adult urologic practice, but are relatively infrequent in children. The natural history and management of these tumors in the pediatric age is different from that of the adults. As result of the successful work of several clinical trial groups in recent decades, there has been a significant improvement in their cure rates. The aim of this article is to review their most significant clinical aspects, as well as to present an update in their management.

The prognostic significance of blastemal predominant histology in initially resected Wilms' tumors: a report from the Study Group for Pediatric Solid Tumors in the Kyushu Area, Japan

BACKGROUND AND PURPOSE

The strategy used to treat pediatric renal tumors in Japan is based on the Japanese Wilms' Tumor Study (JWiTS) protocol, which was based on the National Wilms' Tumor Study (NWTS)-5 regimen. The regimen is characterized by an initial radical operation, followed by adjuvant chemotherapy and radiotherapy. Concerning the histological classification, a new classification based on the International Society of Pediatric Oncology (SIOP) classification was used beginning in 2008. The main points of revision are that the "blastemal predominant type" was classified as an independent category in the Wilms' tumor subtypes. The purpose of this study was to analyze the biological characteristics from the standpoint of the newly established histological classification.

MATERIALS AND METHODS

From 1971 to 2005, 174 cases of Wilms' tumors treated with an initial operation followed by adjuvant therapy were re-evaluated by the new histological classification. Histologically, all these materials showed no secondary changes associated with adjuvant therapy.

RESULTS

According to the new classification, Wilms' tumors were classified into four subtypes, including the mixed type (n=112), epithelial type (n=17), mesenchymal type (n=15), and blastemal predominant type (n=26). The 5 year overall survival rates were as follows; mixed type (90.1%), epithelial type (100%), mesenchymal type (93.3%), and blastemal predominant type (65.4%).

CONCLUSION

The patients with blastemal predominant tumors demonstrated a significantly worse prognosis compared with those of other subtypes. The treatment strategy of blastemal predominant category should be distinguished from the other favorable subtypes.

Relapse of unilateral favorable histology Wilms' tumor: significant clinicopathological factors

PURPOSE

To evaluate the clinicopathological features that indicate relapse and suggest a new risk based therapeutic strategy for unilateral Favorable Histology Wilms Tumor (FH-WT).

MATERIALS & METHODS

Thirty-three patients with unilateral WT were treated in two institutions between 1986 and 2010. Twenty-eight patients with FH-WT received primary nephrectomy according to the National Wilms' Tumor Study (NWTS) or the Japanese Wilms' Tumor Study (JWiTS) protocol. Retrospective analyses of the non-relapsed group (n=23) and the relapsed group (n=5) compared age, gender, tumor laterality, tumor weight, initial tumor stage, known histological subtype, chemotherapy (2 or 3 drugs), and any irradiation delivered. Stages and histological subtypes of the tumors were re-evaluated according to the Japanese staging system.

RESULTS

Five of the twenty-eight tumors relapsed, and one patient died. The initial staging (P=0.029) and the histological subtype (P=0.003) were the only factors indicating relapse. Nine of the twenty-three tumors were histologically classified as blastemal predominant subtype (BPT-WT). Five relapsed.

CONCLUSION

According to the basic Japanese therapeutic strategy, all patients underwent a primary nephrectomy before chemotherapy. This study suggests that the histological subtype pre-treatment "BPT-WT" should be included as a strong indicator of poor prognosis. Such patients should be treated as a high-risk group.

Immunohistochemical expression of GLUT1 and its correlation with unfavorable histology and TP53 codon 72 polymorphism in Wilms tumors

Reprogramming of energy metabolism, such as increased glycolysis, is a hallmark of cancer cells. One mechanism by which cancer cells fuel glycolysis is through increased uptake of glucose across cell membranes via the glucose transporter GLUT1. One of the transcriptional repressors of GLUT1 is wild-type TP53, and cancer-associated loss of function mutations within the DNA-binding domain of TP53 impairs the repressive effect of TP53 on transcriptional activity of the GLUT1 gene promoter. Because TP53 mutations are associated with unfavorable histology (diffuse anaplasia) in Wilms tumors, we hypothesized increased expression of GLUT1 in these tumors. To evaluate this hypothesis, we performed tissue microarray-based immunohistochemistry for GLUT1 in a set of 50 Wilms tumors, including 5 with unfavorable histology. In a subset of 16 favorable histology Wilms tumors, we compared the GLUT1 immunoexpression with TP53 codon 72 polymorphism status. We found consistently stronger immunoexpression of GLUT1 in unfavorable histology Wilms tumors compared to favorable histology Wilms tumors (P  =  0.04). We noted that the favorable histology Wilms tumors with a proline residue at position 72 of TP53 tended to have higher immunoexpression of GLUT1, although this immunoexpression did not reach statistical significance in this small set of cases. In summary, our finding of strong GLUT1 immunoexpression in unfavorable histology Wilms tumors indicates that these tumors are likely to be 2-deoxy-2-((18)F)fluoro-d-glucose avid and that GLUT1 should be evaluated as a therapeutic target for these tumors that otherwise show resistance to conventional therapy.

Minimally invasive nephron-sparing surgery for unilateral Wilms tumor

Minimally invasive surgery (MIS) for nephrectomy has been described since the early 1990s. More recently, MIS has been used for nephron-sparing surgery (NSS) when treating benign conditions. However, reports of NSS using MIS for malignant conditions are sparse. In this report, we describe our retroperitoneal laparoscopic approach for NSS for a localized Wilms tumor.

A study of pathologic risk factors in postchemoreduced, enucleated specimens of advanced retinoblastomas in a developing country

CONTEXT

Advanced cases of retinoblastoma are treated with chemoreduction followed by enucleation. Further adjuvant therapy is recommended in patients with known pathologic risk factors (PRFs).

OBJECTIVES

To determine the PRFs in enucleated specimens after chemoreduction and their association for adverse events of recurrence, metastasis, or death.

DESIGN

This was a retrospective study of 77 enucleation specimens from patients treated between January 2000 and September 2008 with prior chemoreduction that were accessioned in the pathology department of a tertiary referral cancer center with an average follow-up of 24 months. Various PRFs were noted and their association with the development of an adverse event was recorded.

RESULTS

Of 77 patients, (male to female ratio, 51∶26), the incidence of overall PRF was 51.9%, and retrolaminar optic nerve invasion (32.5%), optic nerve cut margin (12.9%), massive choroidal invasion (26%), scleral invasion (23.4%), vitreous seedings (44.2%), and anterior segment invasion (20.8%). Undifferentiated tumor (>60%) was seen in 60.3% of cases (41 of 68 patients with differentiation available). Adverse event occurred in 18 of 72 patients with available follow-up (25%). Retrolaminar optic nerve invasion, optic nerve cut margin involvement, and scleral invasion were independent prognostic factors predicting the occurrence of an adverse event. Undifferentiated tumor (>60%) was a significant risk factor in univariate analysis, which is the unique feature in this study.

CONCLUSIONS

Classic PRF with the addition of a predominant presence from the undifferentiated component were associated with adverse outcomes in retinoblastoma treated with anterior chemotherapy. The latter may represent chemoresistant clones and more intensive adjuvant chemotherapy may be warranted in these patients.

A Surveillance, Epidemiology and End Results (SEER) program comparison of adult and pediatric Wilms' tumor

PURPOSE

To compare the characteristics and outcome of adults and children diagnosed with Wilms' tumor.

METHODS

The Surveillance, Epidemiology and End Results (SEER) database was analyzed for patients diagnosed with Wilms' tumor between 1973 and 2007. Patients were stratified into pediatric (<16 years) or adult (≥16 years) groups. Overall survival was the primary endpoint.

RESULTS

A total of 2342 patients (2190 pediatric and 152 adult) with Wilms' tumor were identified. Adult patients were statistically more likely to be staged as localized than pediatric patients (62.5% vs 44.7%), to not receive any lymph node sampling (57.9% vs 16.2%), and to not receive any radiation treatment (74.3% vs 53.9%). Adults had a statistically worse overall survival (OS) than pediatric patients (5-year OS, 69% vs 88%, P<.001) despite the earlier tumor stage. When stratified by treatment era, the OS of all patients treated after 1981 was statistically higher than those treated before (5-year OS, 75% vs 89%, P<.001). Significant predictors of OS on univariate analysis for adults included treatment era, SEER stage, surgery, and radiation treatment. Significant predictors of OS on multivariate analysis of all patients included adult status (hazard ratio, 4.14; P<.001), treatment era, SEER stage, and surgery.

CONCLUSION

Adults in the SEER database had statistically worse OS than pediatric patients despite previous studies showing comparable outcome when treated on protocol. The worse outcome of SEER adults likely stems from incorrect diagnosis, inadequate staging and undertreatment. We recommend lymph node samplings for all adult Wilms' tumor patients and collaboration with pediatric oncologists.

Pathology, genetics and cytogenetics of Wilms' tumour

Wilms' tumour (WT) is an embryonal cancer of childhood and is thought to be derived from embryonic kidney precursor cells. The Knudson two hit model was initially thought to occur in WT, but findings emerging from genetic and cytogenetic studies in the past two decades have implicated several genetic events. Recent techniques in genetic analysis have improved our ability to characterise changes in genes involved in WT which include WT1, CTNNB1, IGF2 and WTX. These genetic events have not only provided insight into the pathobiology of this malignancy, but the recognition of these candidate genes may offer potential targets for novel therapies. In this review, we will provide an overview of the pathological, genetic and cytogenetic characteristics of WT.

Canine spinal nephroblastoma: long-term outcomes associated with treatment of 10 cases (1996-2009)

OBJECTIVE

To report clinical outcome associated with treatment of canine spinal cord nephroblastoma (CSN).

STUDY DESIGN

Case series.

ANIMALS

Dogs (n=10) with histopathologically confirmed CSN.

METHODS

Records of dogs with CSN were reviewed and clinicopathologic, diagnostic imaging, treatment, outcome, and survival data were collected.

RESULTS

CSN resulted in clinical signs of chronic, progressive T3-L3 myelopathy in young, large breed dogs, with an overrepresentation of German Shepherd Dogs (n=4). All CSN were located between T9 and L2. Dogs treated with cytoreductive surgery (n=6) or radiotherapy (1) survived longer (median, 374 days; range, 226-560 days) than dogs treated palliatively (3; median, 55 days; range, 38-176 days). Tumors confined to an intradural-extramedullary (ID-EM) location were associated with superior survival (n=6; median, 380 days; range, 176-560 days) than tumors with intramedullary (IM) involvement (n=4; median, 140 days; range, 38-269 days). Treatment resulted in temporary improvement in neurologic function in 9 dogs, including all dogs treated surgically, but local disease progression resulted in death of 8 dogs.

CONCLUSIONS

Results of this observational study suggest that surgical cytoreduction and radiotherapy are effective at improving survival in dogs with CSN, and that ID-EM tumors may be associated with a more favorable prognosis than IM neoplasms.

Candidate genes and potential targets for therapeutics in Wilms' tumour

Wilms' tumour (WT) is the most common malignant renal tumour of childhood. During the past two decades or so, molecular studies carried out on biopsy specimens and tumour-derived cell lines have identified a multitude of chromosomal and epigenetic alterations in WT. In addition, a significant amount of evidence has been gathered to identify the genes and signalling pathways that play a defining role in its genesis, growth, survival and treatment responsiveness. As such, these molecules and mechanisms constitute potential targets for novel therapeutic strategies for refractory WT. In this report we aim to review some of the many candidate genes and intersecting pathways that underlie the complexities of WT biology.