Wilms' tumor

Wilms' tumor in a horseshoe kidney

The incidence of horseshoe kidney is about 1 in 400 cases. The presence of Wilms' tumor with a horseshoe kidney is unusual, and the occurrence of Wilms' tumor in a horseshoe kidney is estimated at 0.4 to 0.9% of all Wilms' tumors. We report the case of a 5-year-old boy who presented with a stage IV Wilms' tumor in a horseshoe kidney. The patient was treated with preoperative chemotherapy followed by surgical resection and adjuvant chemotherapy. This case illustrates the role of preoperative chemotherapy for preserving renal function and aims to highlight the multimodality treatment of Wilms' tumor.

Treatment-independent miRNA signature in blood of Wilms tumor patients

Background

Blood-born miRNA signatures have recently been reported for various tumor diseases. Here, we compared the miRNA signature in Wilms tumor patients prior and after preoperative chemotherapy according to SIOP protocol 2001.

Results

We did not find a significant difference between miRNA signature of both groups. However both, Wilms tumor patients prior and after chemotherapy showed a miRNA signature different from healthy controls. The signature of Wilms tumor patients prior to chemotherapy showed an accuracy of 97.5% and of patients after chemotherapy an accuracy of 97.0%, each as compared to healthy controls.

Conclusion

Our results provide evidence for a blood-born Wilms tumor miRNA signature largely independent of four weeks preoperative chemotherapy treatment.

Urinary endothelin-1-like immunoreactivity excretion in Wilms' tumor survivors

BACKGROUND

We evaluated urinary endothelin (ET)-1-like Immunoreactivity (uET-1 L) excretion in Wilms tumor (WT) survivors and investigated its relationships with glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). Glomerular hemodynamics were also assessed by Gomez formulae.

METHODS

Seventeen WT survivors underwent renal sequential scintigraphy for residual kidney function determination including ERPF and GFR. Forty-five healthy individuals were selected as the control group. uET-1 L was measured by radioimmunoassay from the 24-h urine collection.

RESULTS

In WT survivors, uET-1 L excretion was significantly higher than in controls. Significant correlations were found between uET-1 L and ERPF and GFR. Cluster analysis, applied on uET-1 L, identified two different patient groups. Between them, GFR and ERPF were significantly different. No significant difference existed between the two clusters for age and sex, elapsed time from nephrectomy, treatment, or nephrectomy side. Applying Gomez formulae, significant difference was found for afferent and total renal resistance.

CONCLUSIONS

According to our results, uET-1 L seems to be a marker of glomerular injury in patients with renal mass loss revealing renal overload condition. The uET-1 L role in renal damage progression and hemodynamic glomerular worsening in nephrectomized patients should be proven by prospective long-term follow-up studies, even for potential ET-1 receptor antagonist therapeutic use.

SIX1 protein expression selectively identifies blastemal elements in Wilms tumor

BACKGROUND

Wilms tumor (WT) is the most common renal neoplasm in children. Histologically, most WTs consist of three tissue elements: blastema, epithelium, and stroma. Some cases also show diffuse or focal anaplastic features. Previous studies have shown that a predominance of blastemal cells in post-chemotherapy WT specimens is associated with a poor clinical course. However, there is currently no molecular marker for blastemal cells, and risk stratification for post-nephrectomy treatment is therefore often based on clinico-histological parameters alone.

PROCEDURE

In the present study, three public gene expression microarray datasets, including 82 WTs and 8 normal fetal kidneys, were used to establish a consensus gene expression profile of WT. By bioinformatic analyses, 17 genes overexpressed in WT compared to fetal kidney were then selected for evaluation of their protein expression in WT cell lines and in the different histological components in paraffin-embedded WT tissue sections by immunofluorescence.

RESULTS

Most of the evaluated proteins were expressed in all three common histological components. A prominent exception was SIX1, being expressed predominantly in blastemal elements in 24/25 pediatric cases containing blastema. Anaplastic elements exhibited highly variable SIX1-positivity. The SIX2 protein, known to be co-expressed with SIX1 during nephrogenesis, only exhibited blastemal-predominant expression in half of the SIX2 evaluated cases.

CONCLUSIONS

Genes highly expressed in WT compared to fetal kidney are generally overexpressed in all of the three common WT tissue elements. An exception is the predominant expression of SIX1 in blastemal cells, hereby identifying this protein as a candidate marker for blastema.

The surgical management of a stage III Wilms tumor presenting with perforated appendicitis

The majority of the cases of nephroblastoma do not present with abdominal pain. We present a patient with an acute surgical abdomen due to perforated appendicitis and an incidental abdominal mass. He underwent an urgent appendectomy after which tumor specific therapy was successfully initiated.

Transcription factors Sp1 and p73 control the expression of the proapoptotic protein NOXA in the response of testicular embryonal carcinoma cells to cisplatin

Testicular germ cell tumors (TGCTs) are highly responsive to and curable by cisplatin-based chemotherapy even in advanced stages. We have studied the molecular mechanisms involved in the induction of apoptosis in response to cisplatin, and found that proapoptotic Noxa is transcriptionally up-regulated following cisplatin exposure, even in the absence of p53, in NTERA2 cisplatin-sensitive cells but not in 1411HP-resistant cells. Blockade of Noxa reduced the apoptotic response of embryonal carcinoma (EC) NTERA2 cells to cisplatin. A detailed analysis of the Noxa promoter revealed that p73 and Sp1-like factors, Sp1 and KLF6, played key roles in the transcriptional control of this gene. Overexpression of TAp73 induced Noxa whereas the dominant negative isoform ΔNp73, reduced the levels of Noxa after cisplatin exposure in NTERA2 and 2102EP. Interestingly, down-regulation of Sp1 increased Noxa expression in response to cisplatin. However, blockade of KLF6 decreased cisplatin-induced up-regulation of Noxa in EC cell lines. In addition, tissue microarray analyses of TGCTs revealed that expression of Noxa correlates with good clinical prognosis in patients with embryonal carcinoma. Thus, our data show the transcriptional network that regulates Noxa in EC cells, which is key for their apoptotic response to cisplatin-based chemotherapy, and propose Noxa as a predictive factor of therapeutic response.

SIX2 and CITED1, markers of nephronic progenitor self-renewal, remain active in primitive elements of Wilms' tumor

PURPOSE

SIX2 and CITED1 are transcriptional regulators that specify self-renewing nephronic progenitor cells of the embryonic kidney. We hypothesized that SIX2, which promotes and maintains this stem cell population, and CITED1 remain active in Wilms' tumor (WT).

METHODS

To evaluate expression domains and the pathogenic significance of SIX2 and CITED1 across WT, the Children's Oncology Group provided 40 WT specimens of stages I to IV (n = 10 per stage), which were enriched for unfavorable histology (n = 20) and treatment failure (relapse or death, n = 20). SIX2 and CITED1 protein expression was evaluated qualitatively (immunohistochemistry) and quantitatively (Western blot, or WB). Gene transcription was estimated using quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

SIX2 was visualized by immunohistochemistry in 36 (94.7%) of 38 specimens. Protein and messenger RNA expression of SIX2 were quantitatively similar across all stages of disease (P = .48 WB; P = 0.38 qPCR), in favorable or unfavorable histology (P = 0.51 WB; P = 0.58 qPCR), and in treatment failure or success (P = 0.86 WB; P = 0.49 qPCR). Although CITED1 expression paralleled SIX2 qualitatively, no quantitative correlation between SIX2 and CITED1 expression was observed (Spearman correlation coefficient, 0.28; P = 0.08). As in the fetal kidney, overlapping, but also distinct, WT cellular expression domains were observed between SIX2 and CITED1.

CONCLUSION

SIX2 and CITED1 remain active across all disease characteristics of WT. Activity of these genes in WT potentially identifies a population of self-renewing cancer cells that exhibit an embryonic, stemlike phenotype. Taken together, these transcriptional regulators may be fundamental to WT cellular self-renewal and may represent targets for novel therapies that promote terminal differentiation.

Molecular characterization of Wilms' tumor from a resource-constrained region of sub-Saharan Africa

Sub-Saharan African children have an increased incidence of Wilms' tumor (WT) and experience alarmingly poor outcomes. Although these outcomes are largely due to inadequate therapy, we hypothesized that WT from this region exhibits features of biological aggressiveness that may warrant broader implementation of high-risk therapeutic protocols. We evaluated 15 Kenyan WT (KWT) for features of aggressive disease (blastemal predominance and Ki67/cellular proliferation) and treatment resistance (anaplasia and p53 immunopositivity). To explore the additional biological features of KWT, we determined the mutational status of the CTNNB1/β-catenin and WT1 genes and performed immunostaining for markers of Wnt pathway activation (β-catenin) and nephronic progenitor cell self-renewal (WT1, CITED1 and SIX2). We characterized the proteome of KWT using imaging mass spectrometry (IMS). The results were compared to histology- and age-matched North American WT (NAWT) controls. For patients with KWT, blastemal predominance was noted in 53.3% and anaplasia in 13%. We detected increased loss to follow-up (p = 0.028), disease relapse (p = 0.044), mortality (p = 0.001) and nuclear unrest (p = 0.001) in patients with KWT compared to controls. KWT and NAWT showed similar Ki67/cellular proliferation. We detected an increased proportion of epithelial nuclear β-catenin in KWT (p = 0.013). All 15 KWT specimens were found to harbor wild-type CTNNB1/β-catenin, and one contained a WT1 nonsense mutation. WT1 was detected by immunostaining in 100% of KWT, CITED1 in 80% and SIX2 in 80%. IMS revealed a molecular signature unique to KWT that was distinct from NAWT. The African WT specimens appear to express markers of adverse clinical behavior and treatment resistance and may require alternative therapies or implementation of high-risk treatment protocols.

Evaluation of diagnostic performance of CT for detection of tumor thrombus in children with Wilms tumor: a report from the Children's Oncology Group

BACKGROUND

Pre-operative assessment of intravascular extension of Wilms tumor is essential to guide management. Our aim is to evaluate the diagnostic performance of multidetector CT in detection of tumor thrombus in Wilms tumor.

PROCEDURE

The study population was drawn from the first 1,015 cases in the AREN03B2 study of the Children's Oncology Group. CT scans of children with (n = 62) and without (n = 111) tumor thrombus at nephrectomy were independently reviewed by two radiologists, blinded to patient information. Doppler sonography results were obtained from institutional radiology reports, as Doppler requires real-time evaluation. The diagnostic performance of CT and Doppler for detection of tumor thrombus was determined using nephrectomy findings as reference standard.

RESULTS

In the primary nephrectomy group, tumor thrombus detection sensitivity, specificity of CT was 65.6, 84.8%, and Doppler was 45.8, 95.7%, respectively. In this group, sensitivity of CT, Doppler for detection of cavoatrial thrombus was 84.6 and 70.0%, respectively. In the secondary nephrectomy group, tumor thrombus detection sensitivity, specificity of CT was 86.7, 90.6%, and Doppler was 66.7, 100.0%, respectively. In this group, sensitivity of CT, Doppler for detection of cavoatrial thrombus was 96.0 and 68.8%, respectively. Pre-operative Doppler evaluation performed in 108/173 cases, detected 3 cases with intravenous extension (2 in renal vein, 1 in IVC at renal vein level) that were missed at CT.

CONCLUSIONS

CT can accurately identify cavoatrial tumor thrombus that will impact surgical approach. Routine Doppler evaluation, after CT has already been performed, is not required in Wilms tumor.

Preoperative chemotherapy with doxorubicin in Wilms tumor

BACKGROUND

Vincristine and actinomycin-D have long been used as the preoperative chemotherapy before nephrectomy in patients with Wilms tumor (WT). Actinomycin-D is not readily found in Turkey, and delay in treatment, occurring basically from commercial and marketing problems, prompted us to administer alternatives such as doxorubicin, another antitumor antibiotic available in Turkey, to our newly diagnosed patients with WT.

PROCEDURE

Between November 2009 and January 2011, 12 consecutive patients with WT were included in the study. Preoperative chemotherapy consisted of vincristine (1.4 mg/m, days 1, 8, 15, and 22) and doxorubicin (20 mg/m, 1 to 3 d).

RESULTS

All renal tumors showed shrinkage drastically after 4 weeks of preoperative chemotherapy. Surgery of all the patients was uneventful and without any complications. At the end of the median follow-up time of 8 months (range, 6 to 17 mo), all patients are in remission without a sign of the disease.

CONCLUSIONS

Preoperative chemotherapy consisting of vincristine and doxorubicin seems to be successful as a preoperative treatment in achieving shrinkage and reducing the risk of surgical complications. On the basis of the promising results in our study, it is worth administering a similar regimen with further follow-up in larger populations.

Successful disease-specific induced pluripotent stem cell generation from patients with kidney transplantation

Introduction

End-stage renal disease (ESRD) is a major public health problem. Although kidney transplantation is a viable therapeutic option, this therapy is associated with significant limitations, including a shortage of donor organs. Induced pluripotent stem (iPS) cell technology, which allows derivation of patient-specific pluripotent stem cells, could provide a possible alternative modality for kidney replacement therapy for patients with ESRD.

Methods

The feasibility of iPS cell generation from patients with a history of ESRD was investigated using lentiviral vectors expressing pluripotency-associated factors.

Results

In the present article we report, for the first time, generation of iPS cells from kidney transplant recipients with a history of autosomal-dominant polycystic kidney disease (ADPKD), systemic lupus erythematosus, or Wilms tumor and ESRD. Lentiviral transduction of OCT4, SOX2, KLF4 and c-MYC, under feeder-free conditions, resulted in reprogramming of skin-derived keratinocytes. Keratinocyte-derived iPS cells exhibited properties of human embryonic stem cells, including morphology, growth properties, expression of pluripotency genes and surface markers, spontaneous differentiation and teratoma formation. All iPS cell clones from the ADPKD patient retained the conserved W3842X mutation in exon 41 of the PKD1 gene.

Conclusions

Our results demonstrate successful iPS cell generation from patients with a history of ESRD, PKD1 gene mutation, or chronic immunosuppression. iPS cells from autosomal kidney diseases, such as ADPKD, would provide unique opportunities to study patient-specific disease pathogenesis in vitro.

Teratoid Wilms' tumor: case report of a rare variant that can mimic aggressive biology during chemotherapy

Teratoid Wilms' tumor is considered by some as a variant of Wilms' tumor containing at least 50% heterologous differentiated tissue. Fewer than 30 cases have been described. We report a 9-month-old boy with bilateral Wilms' tumors who did not respond to multiagent chemotherapy and underwent right nephrectomy that showed a teratoid Wilms' tumor. The patient continued to survive despite cessation of treatment. The overall predominance of differentiated stromal elements in this subtype of Wilms' tumor might explain the poor response to chemotherapy yet generally favorable outcome. Recognition of this subtype on biopsy might justify earlier surgical intervention that, for bilateral tumors, might allow for greater nephron sparing.

Multicenter study identified molecular blood-born protein signatures for Wilms Tumor

Wilms Tumor (WT) is the most common renal childhood tumor. Recently, we reported a cDNA microarray expression pattern that varied between WTs with different risk histology. Since the Societé Internationale d'Oncologie Pédiatrique (SIOP) in Europe initiates treatment without a histological confirmation, it is important to identify blood-born markers that indicate WT development. In a multicenter study, we established an autoantibody signature by using an array with 1,827 recombinant E. coli clones. This array was screened with sera of patients with WT recruited by SIOP or the Children's Oncology Group (COG). We report an extended number of antigens that are reactive with autoantibodies present in sera from patients with WT. We established an autoantibody signature that separates untreated patients with WT recruited in SIOP from non-WT controls with a specificity of 0.83 and a sensitivity of 0.82 at standard deviations of 0.02 and 0.04, respectively. Likewise, patients recruited in the COG in the United States were separated from the controls with an accuracy of 0.83 at a standard deviation of 0.02. Proteins that were most significant include zinc finger proteins (e.g., ZFP 346), ribosomal proteins and the protein fascin that has been associated with various types of cancer including renal cell carcinoma. Our study provides first evidence for autoantibody signatures for WTs and suggests that these may be most informative before chemotherapy. We present the first multicenter study of autoantibody signatures in patients with WT. We established an autoantibody signature that separates patients with WT from controls.

High-resolution genomic profiling of an adult Wilms' tumor: evidence for a pathogenesis distinct from corresponding pediatric tumors

Wilms' tumor (WT), the most common kidney tumor among children, is characterized by a triphasic morphology consisting of blastemal, epithelial, and stromal components. Adult WT is a rare malignancy displaying similar histological features. We here present the first published high-resolution genomic analysis of a mixed-type adult WT. This revealed a more pronounced genetic complexity than usually observed in children with mixed-type WT. The majority of chromosomes displayed uniparental disomies, and microdeletions were present in genes with known importance for tumor formation (LRP1B, FHIT, and WWOX) or organogenesis (NEGR1 and ZFPM2), abnormalities not previously reported for pediatric WT. Our results indicate that adult WT is a biological entity distinct from the corresponding pediatric tumor type.

Pediatric genitourinary tumors

PURPOSE OF REVIEW

To review the 2009/2010 literature on pediatric genitourinary tumors and highlight the most significant publications.

RECENT FINDINGS

New techniques such as gene expression profiling, PET, nephron-sparing surgery, and stem cell transplantation are being incorporated into contemporary treatments for pediatric patients with genitourinary tumors. Biologic markers are increasingly being used to help with risk stratification of patients. WT1 mutation and 11p15 loss of heterozygosity have been associated with relapse in very low-risk Wilms tumors treated with surgery alone and may help reduce the use of chemotherapy in some children. Discussion continues on the use of fusion gene status to risk stratify alveolar rhabdomyosarcoma. Meta-analysis of the use of high-dose chemotherapy with autologous hematopoetic stem cell rescue in patients with relapsed Wilms tumor and rhabdomyosarcoma suggests that some patients may benefit more from conventional salvage chemotherapy. New agents are needed for patients with high-risk and relapsed disease to improve outcomes.

SUMMARY

In general, the prognosis for patients with pediatric genitourinary tumors is favorable. The elucidation of the molecular abnormalities in these tumors is determining risk stratification, treatment strategies, and candidates for new drug development.

Papillary renal cell carcinoma: report of a rare entity in childhood with review of the clinical management

We present the case of a 9-year-old boy who presents with gross hematuria and is subsequently diagnosed with a papillary (type 1) renal cell carcinoma. Management of renal cell carcinoma in the pediatric population represents a unique challenge, owing to the potential for a genetic predisposition and screening. Herein we discuss novel discoveries with respect to pediatric renal cell carcinoma and their potential impact on screening.

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.

Pediatric genitourinary tumors

PURPOSE OF REVIEW

To review the 2008-2009 literature on pediatric genitourinary tumors and highlight the most significant publications.

RECENT FINDINGS

New techniques such as gene expression profiling, PET, nephron-sparing surgery, and stem cell transplantation are being incorporated into contemporary treatments for pediatric patients with genitourinary tumors. The WTX gene is the most commonly mutated gene in Wilms tumor, and its product enhances Wilms tumor gene 1-mediated transcription. Germline WTX mutations cause an X-linked sclerosing bone dysplasia but do not appear to predispose to Wilms tumor formation. Protocadherin gene clusters on chromosome 5q31 may act as tumor suppressors. In rhabdomyosarcoma, ILK and platelet-derived growth factor receptor-A join the paired box gene 7 and 3-forkhead box O1 fusions as potential therapeutic targets, and muscle-specific microRNAs offer promise as adjuvant therapy. Despite the high cure rate of Wilms tumor, long-term survivors remain at risk of death from various causes.

SUMMARY

In general, the prognosis for patients with pediatric genitourinary tumors is favorable. The elucidation of the molecular abnormalities in these tumors is determining risk stratification, treatment strategies, and candidates for new drug development.

Anaplastic large cell lymphoma: another entity in the differential diagnosis of small round blue cell tumors

We saw in consultation a biopsy specimen from a 6-year old girl with anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL). The tumor arose in soft tissue of the neck, and diagnostic tissue was obtained by core needle biopsy. Histologically, the neoplasm was cellular without pattern. Immunohistochemical workup with a large panel of antibodies at another institution showed immunoreactivity for NB84 and neuron specific enolase (dim). Antibodies specific for CD3, CD20, and CD45/LCA were negative; CD30 or ALK were not assessed. Electron microscopy showed cytoplasmic structures thought to be neurosecretory granules. The neoplasm was interpreted initially as a neuroblastoma. At the time of our review, we considered the possibility of ALCL. Immunohistochemical analysis for CD30 showed bright, uniform expression and ALK was positive in a nuclear and cytoplasmic pattern, confirming the diagnosis of ALK+ ALCL. The purpose of this review is to discuss ALK+ ALCL and many of the other entities included under the rubric of small round blue cell tumor, with a focus on tumors that occur in children.