Principles of Wilms' tumor biology

Nephroblastoma of the Big Child, a Rare Entity: About a Case

Nephroblastoma is a renal blast tumor, the most common malignant renal tumor in children between 1 and 5 years of age. The average age of onset is 3.5 years, rarely occurring in children over 10 years of age. Its treatment is a model of medical-surgical collaboration. The prognostic factors are mainly the stage but recent studies have also shown that the advanced age of the child is a negative prognostic factor. We report a case of a 14-year-old child who presented with pain with swelling of the right hypochondrium, ultrasound showed a heterogeneous right retroperitoneal mass, MRI showed a large retroperitoneal tumor process with a right renal origin, in heterogeneous T2 signal, in T1 hyposignal, diffusion restricted, containing necrotic areas and heterogeneously enhancing after injection, responsible for pyelocalic dilatation and right renal venous thrombosis, extended to the IVC and the right atrium, with adenopathies, suggesting first a sarcoma. The extension workup showed pulmonary nodules of secondary appearance. An echo-guided biopsy was performed and the anatomopathological study confirmed the diagnosis of nephroblastoma.

Brain Metastasis of Wilms Tumor in Adult

BACKGROUND

Wilms tumor is a rare renal tumor in adults. To the best of our knowledge, only a small number of cases of brain metastasis have been reported in the literature. We report the case of a 29-year-old female with headache and dizziness, with a parietal mass and pathologic diagnosis of Wilms tumor metastasis.

CASE DESCRIPTION

The patient was admitted with a 3-month history of lumbar pain and 2 months of progressive headache associated with dizziness. Abdomen magnetic resonance imaging showed a renal mass. Post nephrectomy, the neurologic signs worsened and a head magnetic resonance imaging presented in the right parietal lobe, convexity, heterogeneous lesion with little perilesional edema. The patient underwent a complete surgical resection with success. The adjuvant treatment was chemotherapy.

CONCLUSIONS

Few cases of brain metastasis of Wilms tumor exist in the literature. Surgical management is considered in cases with intracranial hypertension or focal signs. The adjuvant treatment options are immunotherapy and chemotherapy.

Investigating the dysfunctional pathogenesis of Wilms' tumor through a multidimensional integration strategy

Background

Wilms' tumor (WT) is a common kidney tumor in early childhood which is characterized by multiple congenital anomalies and syndromes. With the continuous improvement of medical standards, the cure rate and survival period of WT have increased. However, its molecular mechanism is still elusive.

Methods

A comprehensive multidimensional integration strategy was used to comprehensively analyze the mechanisms of WT.

Results

By integrating the potential pathogenic genes of kidney cancer and performing co-expression analysis on the disease-related genes, 23 functional modules were obtained. All the genes were differentially expressed in WT, and were mainly involved in many biological processes and signaling pathways, such as Wnt/β-catenin, mTOR/ERK and calcineurin. Additionally, based on the relationship between transcriptional and post-transcriptional regulatory systems, in functional modules, transcription factors (TFs) including STAT3, HDAC1 and SP1 as well as non-coding RNAs (ncRNAs) such as miR-335-5p, miR-21-5p and TUG1 were identified. Finally, potential drugs for these multifactor regulated dysfunctional modules which may have certain pharmacological or toxicological effects on WT such as cisplatin, sorafenib, and zinc were predicted.

Conclusions

A multidimensional dysfunction mechanism, involving disease-related genes, TFs and ncRNAs was revealed in the pathogenesis of WT. Functional modules were used to predict potential drugs which can be used in personalized therapy and drug delivery. This study explored the pathogenesis of WT from a new perspective, and provides new candidate targets and therapeutic drugs for improving the cure rate of WT.

Relapsed Wilms' tumor with multiple brain metastasis

Wilms' tumor is the most common malignant renal tumor in childhood. The brain metastasis of a Wilms' tumor with anaplastic histopathology is rare. We present the case of an 8-year-old girl with Wilms' tumor, who presented with multiple brain metastases 5 years after her primary diagnosis. The brain masses were diagnosed after a generalized tonic-clonic seizure attack. The big solid mass in the cerebellum was resected, and whole-brain radiotherapy was performed, after which, she succumbed to her disease. In the case of clinical suspicion, cranial surveillance should be included in the routine clinical work-up for Wilms' tumor. Combined aggressive therapy (surgery+radiotherapy+chemotherapy) should be applied whenever possible, for both better survival and palliative aspects.

Human renal cancer stem cells

Cancer stem cells (CSCs), isolated in renal carcinomas, exhibit tumor-initiating capabilities and pluripotency. No specific CSC markers have been identified so far; therefore, their characterization is mainly based on functional studies. As they are resistant to chemo and radio therapy, renal CSCs may have a relevant role in tumor establishment, progression, and recurrence. CSCs were also shown to contribute to intra-tumor vasculogenesis through an endothelial differentiation and to favor the generation of the pre-metastatic niche through the release of exosomes/microvesicles.

Wilms tumor--a renal stem cell malignancy?

Wilms' tumor (WT; nephroblastoma) is the most common pediatric renal malignancy and rated fourth in overall incidence among childhood cancers. It is viewed as a prototype of differentiation failure in human neoplasia as it recapitulates the histology of the nephrogenic zone of the growing fetal kidney. The cellular origin of WT is unclear. However, recent genomic, genetic and epigenetic studies point to an early renal stem/progenitor cell that undergoes malignant transformation as the source for WT. In this context, classical WT shares genes and pathways activated in progenitors committed to the renal lineage. However, direct proof and characterization of the WT initiating cell have remained elusive. Novel methodologies recently adopted from the cancer stem cell scientific field, including the analysis of sorted single human tumor cells, have been applied to WT. These have enabled the identification of cell sub-populations that show similarities-in terms of molecular marker expression-to human fetal kidney progenitors and are, therefore, likely to be derivatives of the same lineage. Further elucidation of the WT cancer stem cell or the cell of origin in human tumors and in transgenic mouse models that generate murine tumors may not only provide novel therapeutic targets but also shed light on the normal kidney stem cell.

Multiple imprinted and stemness genes provide a link between normal and tumor progenitor cells of the developing human kidney

Wilms' tumor (WT), the embryonic kidney malignancy, is suggested to evolve from a progenitor cell population of uninduced metanephric blastema, which typically gives rise to nephrons. However, apart from blastema, WT specimens frequently contain cells that have differentiated into renal tubular or stromal phenotypes, complicating their analysis. We aimed to define tumor-progenitor genes that function in normal kidney development using WT xenografts (WISH-WT), in which the blastema accumulates with serial passages at the expense of differentiated cells. Herein, we did transcriptional profiling using oligonucleotide microarrays of WISH-WT, WT source, human fetal and adult kidneys, and primary and metastatic renal cell carcinoma. Among the most significantly up-regulated genes in WISH-WT, we identified a surprising number of paternally expressed genes (PEG1/MEST, PEG3, PEG5/NNAT, PEG10, IGF2, and DLK1), as well as Meis homeobox genes [myeloid ecotropic viral integration site 1 homologue 1 (MEIS1) and MEIS2], which suppress cell differentiation and maintain self-renewal. A comparison between independent WISH-WT and WT samples by real-time PCR showed most of these genes to be highly overexpressed in the xenografts. Concomitantly, they were significantly induced in human fetal kidneys, strictly developmentally regulated throughout mouse nephrogenesis and overexpressed in the normal rat metanephric blastema. Furthermore, in vitro differentiation of the uninduced blastema leads to rapid down-regulation of PEG3, DLK1, and MEIS1. Interestingly, ischemic/reperfusion injury to adult mouse kidneys reinduced the expression of PEG3, PEG10, DLK1, and MEIS1, hence simulating embryogenesis. Thus, multiple imprinted and stemness genes that function to expand the renal progenitor cell population may lead to evolution and maintenance of WT.

The kidney, cancer, and the eye: current concepts

Herein, we review the associations between the kidney, renal cancers, and the eye. Renal cancers have been reported to metastasize to the eye and the orbit. As these tumors can be confused with other amelanotic or vascular tumors, a high index of suspicion is required for early detection and management of the primary tumor. We discuss the physiology of metastases, clinical features and management of metastatic disease. A variety of ocular anomalies have been associated with renal disease. Wilms tumor, a renal tumor of childhood, can present with aniridia, which may be the first clue leading to the diagnosis of the primary tumor. Paraneoplastic syndromes are common manifestations of renal cancers and can present as retinopathies and neuro-ophthalmic disorders. Multiple cancer syndromes involve both the eye and the kidney. For example, the diagnosis of von Hippel retinal tumors can lead to a systemic evaluation and discovery of associated visceral tumors. The prognosis, screening, and counseling of such patients is discussed. Newer systemic treatments available for renal tumors, such as interferon alfa, may lead to ocular side effects including retinopathy. These patients require periodic ophthalmic examinations. This review demonstrates the essential role of the ophthalmologist, for early diagnosis and treatment that can help reduce the morbidity and mortality associated with kidney tumors and renal-associated disease.

The spectrum of pediatric tumors in infancy, childhood, and adolescence: a comprehensive review with emphasis on special techniques in diagnosis

The spectrum of pediatric tumors varies considerably, from those derived from blastemal cells in various organ systems to proliferations of soft tissue supporting cells to hamartomatous processes that mimic malignant tumors. Small round cell tumors are often undifferentiated or poorly differentiated, making it difficult sometimes to provide a definitive diagnosis. Both benign and malignant tumors require a coordinated method for diagnosis, and need a comprehensive evaluation to provide the most appropriate diagnosis for designing therapy and predicting prognosis. Pediatric tumors require the integration of routine histopathologic examination with histochemical, immunocytochemical, ultrastructural, cytogenetic, and diagnostic molecular pathology techniques. This review provides updated guidelines with respect to the application of these special techniques in this rapidly evolving diagnostic arena.

Frequent overexpression of cyclin D2/cyclin-dependent kinase 4 in Wilms' tumor

The expression status of the three cyclin D genes (CCND1, CCND2 and CCND3), the two cyclin D-dependent kinase genes (CDK4 and CDK6) and the p16(INK4a) gene was studied in a series of 47 Wilms' tumors, 16 normal mature kidneys and two fetal kidneys. We showed predominant overexpression of CCND2 and CDK4 compared to CCND1/D3 and CDK6 respectively. We found a specific correlation between relapse and CDK4 overexpression, but not CDK6 overexpression. We did not identify any methylation of the p16(INK4a) promoter. This suggests that dysregulation of CCND2 and CDK4 plays a specific role in WT tumorigenesis.

Differential expression of a novel ankyrin containing E3 ubiquitin-protein ligase, Hace1, in sporadic Wilms' tumor versus normal kidney

We have analyzed the chromosome 6q21 breakpoint of a non-constitutional t(6;15)(q21;q21) rearrangement in sporadic Wilms' tumor. This identified a novel gene encoding a protein with six N-terminal ankyrin repeats linked to a C-terminal HECT ubiquitin-protein ligase domain. We therefore designated this gene HACE1 (HECT domain and Ankyrin repeat Containing E3 ubiquitin-protein ligase 1). HACE1 is widely expressed in human tissues, including mature and fetal kidney. We show that Hace1 protein possesses intrinsic ubiquitin ligase activity, utilizes UbcH7 as a candidate partner E2 enzyme and localizes predominantly to the endoplasmic reticulum. Although the HACE1 locus was not directly interrupted by the translocation in the index Wilms' case, its expression was markedly lower in tumor tissue compared with adjacent normal kidney. Moreover, HACE1 expression was virtually undetectable in the SK-NEP-1 Wilms' tumor cell line and in four of five additional primary Wilms' tumor cases compared with patient-matched normal kidney. We found no evidence of HACE1 mutations or deletions, but hypermethylation of two upstream CpG islands correlates with low HACE1 expression in tumor samples. Our findings implicate Hace1 as a novel ubiquitin-protein ligase and demonstrate that its expression is very low in primary Wilms' tumors.

Management of Wilms' tumour: current practice and future goals

Most patients with Wilms' tumour in Europe and North America can be cured with treatment and subsequently lead a normal adulthood. However, for some, therapy as applied today results in long-term side-effects and creates a substantial burden on quality of life. Therefore, investigators involved in the management of patients with Wilms' tumour are increasingly focusing their efforts on curtailing the long-term sequelae of therapy. This aim has been achieved by lowering the total amount of chemotherapy, radiotherapy, or both administered to patients who have characteristics associated with favourable outcome. Although excellent survival has been maintained, many patients receive less therapy today than patients with similar characteristics did a decade or two ago. Better understanding of the biological processes that lead to this childhood cancer will allow further improvements in its management.

Wilms' tumor in a case with Möbius' syndrome associated with arthrogryposis and mega cisterna magna

Möbius' syndrome is a rare congenital anomaly characterized by paralysis of the 7th and other cranial nerves and musculoskeletal abnormalities. We report a patient with Möbius' syndrome associated with arthrogryposis and mega cisterna magna in addition to the classic components of this syndrome. The case is interesting because she developed Wilms' tumor at 21 months of age. To our knowledge, this is the first case of this association reported in the literature.

Responsiveness of chemotherapy based on the histological type and Wilms' tumor suppressor gene mutation in bilateral Wilms' tumor

To clarify a characteristic of bilateral Wilms' tumor (WT), we examined the clinical and histological features, chemotherapy response and mutations in Wilms' tumor suppressor gene (WT1) in five patients. Deoxyribonucleic acid was extracted from peripheral lymphocytes and tumor samples, and direct DNA sequencing was performed to detect WT1 mutations. Paraffin sections were stained with H&E for histological review and immunostained with anti-WT1, anti-Ki-67, anti-S-100 protein and antimyogenin antibodies. In contrast to the single case of epithelial-type WT, the other four cases were fetal rhabdomyomatous nephroblastoma (FRN) or contained a premature skeletal muscle component and appeared to be resistant to chemotherapy because there was no reduction in tumor volume. However, after chemotherapy, most of the tumor components changed into mature striated muscle cells, most of which immunostained almost completely negative for Ki-67. All four cases had the same point mutation of WT1. From our results, the histological findings correlated with WT1 mutations in bilateral WT. The tumor volume of FRN did not decrease in response to chemotherapy. It is possible to predict the chemotherapy response by examining bilateral WT for WT1 mutations and the histological characteristics of tumors.

Combined cytogenetic and array-based comparative genomic hybridization analyses of Wilms tumors: amplification and overexpression of the multidrug resistance associated protein 1 gene (MRP1) in a metachronous tumor

Tumor samples from a variety of Wilms tumors (WT) obtained from three patients were analyzed by cytogenetic and array-based comparative genomic hybridization (CGH) methods. The tumors represented different stages of tumorigenesis and included a unilateral primary WT and contralateral nephrogenic rest (case 1), a primary WT and a contralateral metachronous WT (case 2), and a recurrent WT with lung metastases (case 3). All six specimens exhibited abnormal karyotypes characteristic of different WT levels of progression. Array-based CGH examinations of 57 genes that are commonly amplified in various cancers revealed a 2.6-fold genomic amplification of the multidrug resistance-associated protein 1 (MRP1) gene in the metachronous WT, but no amplification in the primary tumor. This sole amplification event in our series was also confirmed by Southern blot analysis. Furthermore, quantitative reverse transcriptase polymerase chain reaction showed a sixfold overexpression of the MRP1 gene in this metachronous WT relative to the primary tumor. Our findings suggest that for most of the genes examined in this series genomic amplification does not play a role in WT pathogenesis. Isolated amplification and overexpression of the MRP1 gene in the metachronous WT, however, suggest that this gene may be an important factor in the development and progression of metachronous tumors.

Imaging of neuroblastoma and Wilms' tumor

Neuroblastoma and Wilms' tumor are the most common noncentral nervous system solid tumors in children. Imaging plays a crucial role in the evaluation of the primary tumor and regional and metastatic disease. There is a growing body of literature supporting the use of MRI as the technique of choice for the evaluation of local and regional disease in children with suspected neuroblastoma; however, in children with suspected Wilms' tumor, MRI will likely continue to play a role as a problem-solver when the results of CT are equivocal or indeterminant.

Brain metastases in Wilms' tumor: case report and literature review

A 2-year-old girl who had a stage 2, favorable-histology Wilms tumor diagnosed when she was age 10 months presented with multiple brain metastases at second recurrence. She had been treated with combined radiotherapy, surgery, and chemotherapy; at 2 months after treatment, recurrent disease developed in the central nervous system and she died. Brain metastases are rare in the natural history of Wilms tumor. Although it does not appear that cerebral metastases are a barrier to tumor eradication and long-term survival if treated with combined modality therapy, treatment should be individualized.

Wilms' tumor (nephroblastoma)

Wilms' tumor (nephroblastoma) is a subject which continues to challenge clinicians in their attempts to achieve the best survival of their patients, while minimizing morbidity. Overall survival of over 85% of all children can now be achieved using combination therapy with chemotherapy, surgery, and in some cases radiotherapy. Recent reviews of two multi-institutional, multinational trials (the International Society of Pediatric Oncology and the National Wilms' Tumor Study Group) are discussed in this article, in which their current approaches to therapy are presented. In addition to these clinical advances, the genetic and molecular features of Wilms' tumor continue to provide insight into the biology of nephroblastoma and into neoplasia in general. A recent review of these aspects of the field is provided.

Pediatric genitourinary tumors

Each year advances are made in the evaluation and management of genitourinary tumors in children. There is increased understanding of molecular and genetic processes in tumorigenesis. In addition, knowledge concerning the current treatment modalities is increasing, thus allowing us to tailor treatments in order to decrease long-term complications. In this article, we review this past year's literature regarding pediatric genitourinary tumors with emphasis on Wilms tumor, rhabdomyosarcoma, and testicular tumors.