Case report: value of gene expression profiling in the diagnosis of atypical neuroblastoma

BACKGROUND

Nephroblastoma and neuroblastoma belong to the most common abdominal malignancies in childhood. Similarities in the initial presentation may provide difficulties in distinguishing between these two entities, especially if unusual variations to prevalent patterns of disease manifestation occur. Because of the risk of tumor rupture, European protocols do not require biopsy for diagnosis, which leads to misdiagnosis in some cases.

CASE PRESENTATION

We report on a 4½-year-old girl with a renal tumor displaying radiological and laboratory characteristics supporting the diagnosis of nephroblastoma. Imaging studies showed tumor extension into the inferior vena cava and bilateral lung metastases while urine catecholamines and MIBG-scintigraphy were negative. Preoperative chemotherapy with vincristine, actinomycine D and adriamycin according to the SIOP2001/GPOH protocol for the treatment of nephroblastoma was initiated and followed by surgical tumor resection. Histopathology revealed an undifferentiated tumor with expression of neuronal markers, suggestive of neuroblastoma. MYCN amplification could not be detected. DNA-microarray analysis was performed using Affymetrix genechip human genome U133 plus 2.0 and artificial neural network analysis. Results were confirmed by multiplex RT-PCR.

RESULTS

Principal component analysis using 84 genes showed that the patient sample was clearly clustering with neuroblastoma tumors. This was confirmed by hierarchical clustering of the multiplex RT-PCR data. The patient underwent treatment for high-risk neuroblastoma comprising chemotherapy including cisplatin, etoposide, vindesine, dacarbacine, ifosfamide, vincristine, adriamycine and autologous stem cell transplantation followed by maintenance therapy with 13-cis retinoic acid (GPOH NB2004 High Risk Trial Protocol) and is in complete long-term remission.

CONCLUSION

The use of gene expression profiling in an individual patient strongly contributed to clarification in a diagnostic dilemma which finally led to a change of diagnosis from nephroblastoma to neuroblastoma. This case underlines the importance of gene-expression profiling in the correct diagnosis of childhood neoplasms with atypical presentation to ensure that adequate treatment regimens can be applied.

Inhibitory effect of Par-4 combined with cisplatin on human Wilms' tumor cells

Wilms' tumor is associated with a high treatment success rate, but there is still a risk of recurrence. Cisplatin, which is one of the chemotherapeutic agents used for its treatment, is associated with a very high rate of resistance. Par-4 (prostate apoptosis response 4) is a tumor suppressor, which is capable of sensitizing tumor cells to chemotherapy. Therefore, the aim of this study was to determine whether combined treatment with Par-4 and cisplatin is effective for inhibiting growth of Wilms' tumor. Wilms' tumor and control cell samples were collected and analyzed by immunofluorescence assay and immunohistochemistry. Total proteins extracted from cultured cells were analyzed using western blotting and flow cytometry. In addition, a mouse xenograft model was established. We discovered significantly low expression of Par-4 in the tumor tissue, which was positively correlated with high expression of GRP78 (glucose-regulated protein 78). In addition, we found that ectopic Par-4 co-localized with cell surface GRP78 and induced high expression of the endoplasmic reticulum proteins ATF4 and BAX, which activated the endoplasmic reticulum apoptosis pathway. Moreover, treatment with ectopic Par-4 and cisplatin suppressed xenograft growth in nude mice. In conclusion, our results showed that Par-4 overexpression and cisplatin had a synergistic effect on SK-NEP-1 cells, as a result of which cell growth was inhibited and cellular apoptosis was induced. Thus, in vitro and in vivo upregulation of Par-4 expression is indispensable for the trafficking of GRP78 to the cell membrane and subsequent apoptosis of cancer cells.

[Wilms' tumour: A review of 15 years recent experience]

INTRODUCTION

Wilms' tumour is the most frequent renal tumour in children. Multi-modal treatment includes chemotherapy and surgery, with or without radiotherapy. The survival is excellent, with rates exceeding 90%. A review is presented on our experience over the last 15 years of treating Wilms' tumour in Hospital Niño Jesús, Madrid.

PATIENTS AND METHODS

A retrospective study was conducted on 40 consecutive paediatric patients diagnosed with nephroblastoma between 2002 and 2016 in the Hospital Niño Jesús in Madrid. The clinical characteristics, diagnostic methods, treatment, and follow-up were analysed.

RESULTS

Of the 40 patients, 23 were boys, with a median age at diagnosis of 2.5 years (range, 4 months-15 years). Three patients underwent initial nephrectomy, three received a fine needle aspiration biopsy, followed by chemotherapy, and 34 patients started pre-operative chemotherapy directly. The median follow-up of the patients was 6.75 years (range, 10 months - 13.92 years). Two patients died from disease progression. There were no treatment-related deaths. Overall survival and event-free survival at 5 years was 94.6±3.7% and 89.4±5%, respectively.

CONCLUSION

Wilms' tumour treatment is a success of modern medicine, currently achieving a survival rate of 95% in our series.

Inferior vena cava involvement in children with Wilms tumor

OBJECTIVES

Retrospective review of children with WT thrombus involving the IVC.

METHODS

We reviewed the charts of 123 patients with WT diagnosed between January 2006 and December 2015. Patients with caval tumor thrombus were identified, demographic data, radiological images, extent of thrombus, chemo- and radiotherapy, surgical approach, pathology reports and outcomes were analyzed.

RESULTS

IVC involvement was identified in 11 patients (9%). Left-sided tumors were more common (55%). Sensitivity of CT scan in thrombus identification was 64%. Neoadjuvant chemotherapy was the primary mode of treatment with 19% reduction of primary tumor size, thrombus resolution in four and regression in six patients. No thrombus progression was observed. Delayed surgical treatment was either nephro-ureterectomy (nine patients) or partial nephrectomy in patients with bilateral WT (two patients). During surgery, thrombectomy and intimal stripping achieved local control in patients with persistent caval tumor. Cardiopulmonary bypass was not needed in patients with initial atrial involvement (five patients). Despite adherence and invasion of tumor thrombus to IVC wall, only one patient required segmental vein resection. All patients eventually achieved CR, none had local relapse. One patient had lung relapse treated to complete remission. The 3-year EFS is 85.7 ± 13.2% and the 3-year OS is 100%.

CONCLUSION

IVC tumor thrombus in patients with WT was managed successfully using preoperative chemotherapy followed by surgery with minimal aggressive approach. Luminal thrombus removal and intimal stripping supplanted by local radio boost when indicated seem to be adequate tools for local control with documented good overall outcomes.

Respiratory-gated bilateral pulmonary radiotherapy for Ewing's sarcoma and nephroblastoma in children and young adults: Dosimetric and clinical feasibility studies

PURPOSE

Bilateral pulmonary radiotherapy in children and young adults aims to reduce the recurrence of lung metastases. The radiation field includes liver tissue, which is sensitive to even low radiation doses. We investigated the feasibility of respiratory gating radiotherapy using voluntary deep inspiration breath hold and its toxicity in these patients.

PATIENTS AND METHOD

A retrospective clinical review was conducted for all patients who had undergone bilateral pulmonary radiotherapy, with or without deep inspiration breath hold, treated in our institution between October 1999 and May 2012. A dosimetric study was conducted on seven consecutive children using 4D-scan data on free-breathing and a SpiroDyn'RX-system-scan on deep inspiration breath hold. A radiation treatment of 20Gy was simulated.

RESULTS

Concerning the clinical study, seven patients of mean age 11.9 years (range: 4.9-21.1 years) were treated with free-breathing and ten patients of mean age 15.6 years (range: 8.6-19.7 years) were treated with deep inspiration breath hold for mainly Ewing sarcoma and nephroblastoma. Within six months of radiotherapy, all patients experienced mild liver toxicity (grade 1 or 2 altered levels of alanine/aspartate aminotransferase [n=8 of 9] or cholestasis [n=1 of 9]), which resolved completely with no difference between deep inspiration breath hold and free-breathing technique. Over a median follow-up of 2.6 years (range: 0.1-9.3 years), four patients died from disease progression (mean 1.5 years post-radiotherapy [range: 1.1-1.6 years]) and three experienced grade III-V lung toxicity. Concerning the dosimetric study, the irradiated liver volume was significantly lower with deep inspiration breath hold than free-breathing, for each isodose (V5: 73.80% versus 86.74%, P<0.05; V20: 5.70% versus 26.44%, P<0.05).

CONCLUSIONS

The dosimetric data of respiratory-gated bilateral pulmonary radiotherapy showed a significantly spare of normal liver tissue. Clinical data showed that this technique is feasible even in young children. However, no liver toxicity difference between deep inspiration breath hold and free-breathing was shown.

Autophagy Inhibition in Childhood Nephroblastoma and the Therapeutic Significance

BACKGROUND

Autophagy is a physiological pathway characterized by lysosomedependent self-digestion to recycle damaged or superfluous cellular content. Deregulation of autophagy hampers the maintenance of cellular homeostasis and contributes to tumorigenesis. However, during anticancer therapy, autophagy activation contributes to development of resistance. Thus autophagy has been recognized as an important pathway and a therapeutic target in cancer. Nephroblastoma (Wilm's tumor) is a common childhood malignancy. The role of autophagy in nephroblastoma is largely uninvestigated.

OBJECTIVE

This study is to investigate the change of autophagy level in nephroblastoma, and whether autophagy could be a therapeutic target in anaplastic nephroblastoma.

METHOD

In clinical samples of childhood nephroblastoma, autophagy activity was evaluated by the expressions of selected autophagy markers as well as the presence of autophagosome ultrastructure. Use of autophagy inhibitors alone and in combination with conventional chemotherapeutics, was studied both in vivo and in vitro.

RESULTS

In nephroblastoma, there was decrease in the Beclin 1 level and the number of autophagosomes, suggesting autophagy inhibition. Furthermore, in two anaplastic nephroblastoma cell lines, G401 and SK-NEP1, autophagy inhibitors further enhanced the efficacy of conventional chemotherapeutics including vincristine and cisplatin. In G401 tumor model established in nude mice, combinational use of chloroquine, an inhibitor of autophagy degradation, further decreased the tumor mass compared with single use of the chemotherapeutics vindesine, although no statistical significance was achieved.

CONCLUSION

Our results suggest that autophagy deregulation is involved in nephroblastoma, and targeting autophagy can serve as a potential adjuvant strategy for the highly malignant cases.

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.

Apparent diffusion coefficient as it relates to histopathology findings in post-chemotherapy nephroblastoma: a feasibility study

BACKGROUND

Nephroblastomas represent a group of heterogeneous tumours with variable proportions of distinct histopathological components.

OBJECTIVE

The purpose of this study was to investigate whether direct comparison of apparent diffusion coefficient (ADC) measurements with post-resection histopathology subtypes is feasible and whether ADC metrics are related to histopathological components.

MATERIALS AND METHODS

Twenty-three children were eligible for inclusion in this retrospective study. All children had MRI including diffusion-weighted imaging (DWI) after preoperative chemotherapy, just before tumour resection. A pathologist and radiologist identified corresponding slices at MRI and postoperative specimens using tumour morphology, the upper/lower calyx and hilar vessels as reference points. An experienced reader performed ADC measurements, excluding non-enhancing areas. A pathologist reviewed the corresponding postoperative slides according to the international standard guidelines. We tested potential associations with the Spearman rank test.

RESULTS

Side-by-side comparison of MRI-DWI with corresponding histopathology slides was feasible in 15 transverse slices in 9 lesions in 8 patients. Most exclusions were related to extensive areas of necrosis/haemorrhage. In one lesion correlation was not possible because of the different orientation of sectioning of the specimen and MRI slices. The 25% ADC showed a strong relationship with percentage of blastema (Spearman rho=-0.71, P=0.003), whereas median ADC was strongly related to the percentage stroma (Spearman rho=0.74, P=0.002) at histopathology.

CONCLUSION

Side-by-side comparison of MRI-DWI and histopathology is feasible in the majority of patients who do not have massive necrosis and hemorrhage. Blastemal and stromal components have a strong linear relationship with ADC markers.

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.

Multicystic dysplastic kidney: Assessment of the need for renal scintigraphy and the safety of conservative treatment

OBJECTIVES

To assess the need for implementing renal scintigraphy in the diagnosis of the multicystic dysplastic kidney (MCDK) and the safety of its conservative treatment.

MATERIAL AND METHODS

A retrospective study of patients with unilateral MCDK was conducted at our centre from January 2005 to August 2015. We calculated the positive predictive value (PPV) of ultrasonography, taking renal scintigraphy and pathology as the gold standard. We calculated a survival curve according to the Kaplan-Meier method to assess the annual probability of spontaneous resolution of the multicystic kidney.

RESULTS

Fifty-six patients were identified, 48 (85.7%) of whom had a prenatal diagnosis. Thirty eight (67.9%) of the patients were males, and the left side was affected in 33 (58.9%) of the patients. We observed associated urological abnormalities in 22 (39.29%) patients, with vesicoureteral reflux the most common (8, 14.29%). Seven patients (12.5%) developed renal failure. Forty-nine (87.5%) patients developed compensatory contralateral renal hypertrophy. Of the 33 patients who underwent surgery, the pathology results confirmed the MCDK diagnosis in 32. Compared with scintigraphy and pathology, the PPV of ultrasonography was 100% and 97%, respectively. The rate of spontaneous involution was 5.4% at 3 months of life, 11.3% at 2 years and 38.4% at 5 years.

CONCLUSIONS

In our experience, the conservative treatment of MCDK, until at least 5 years of age, is safe. Our data suggest that performing scintigraphy is not required for these patients, which means lower radiation exposure, as well as financial savings.

The association between nephroblastoma-specific outcomes and high versus low volume treatment centers

BACKGROUND

Though the volume-outcome relationship has been well-established in adults, low mortality rates and small sample sizes have precluded definitive demonstration in children. This study compares treatment-specific factors for children with nephroblastoma at high (HVC) versus low volume centers (LVC).

METHODS

We performed a retrospective cohort study comparing patients ≤18years with unilateral nephroblastoma treated at HVCs and LVCs using the National Cancer Data Base (1998-2012). Definitions of HVCs included performing above the median, the upper two quartiles, and the highest decile of nephroblastoma resections. Outcomes included nodal sampling, margin status, time to chemotherapy and radiation, and survival. Statistical analyses included χ², t-tests, generalized linear, and Cox regression models (p<0.05).

RESULTS

Of 2911 patients from 210 centers, 1443 (49.6%) were treated at HVCs. There was no difference in frequency of preoperative biopsy or days to radiation (p>0.05). High volume centers were more likely to perform nodal sampling (RR 1.04, 95%CI 1.01-1.08) and had fewer days to chemotherapy (RR 0.80, 95%CI 0.69-0.93). Five-year survival was similar (HVC: 0.93, 95%CI 0.92-0.94; LVC: 0.93, 95%CI 0.91-0.94).

CONCLUSIONS

HVCs were more likely to perform nodal sampling and had fewer days to chemotherapy. There was no difference in days to radiation or survival between centers.

LEVEL OF EVIDENCE

Level II (retrospective prognosis study).

K-Ras, H-Ras, N-Ras and B-Raf mutation and expression analysis in Wilms tumors: association with tumor growth

Nephroblastoma (Wilms tumor) is a kidney neoplasia, predominately occurring at very young age, resulting from the malignant transformation of renal stem cells. The Ras proto-oncogenes and B-Raf are members of an intracellular cascade pathway, which regulates cell growth and differentiation, and ultimately cancer development. Our objective was to determine the mutation rate and to measure the mRNA levels of the three Ras genes and of B-Raf in formalin-fixed paraffin-embedded tissue samples from 32 patients with nephroblastoma and 10 controls. No mutations were detected in the four studied genes among our Wilms tumors cases, while Ras and B-Raf expression was higher in malignant samples versus controls. Statistical analysis revealed a positive correlation of K-Ras (p < 0.001) and B-Raf (p = 0.006) with tumor size, a negative correlation of K-Ras (p = 0.041) and H-Ras (p = 0.033) with the percentage of tissue necrosis, and an association of N-Ras (p = 0.047) and B-Raf (p = 0.044) with tissue histology. From the above, we deduce that although Ras and B-Raf mutations are rare events in Wilms tumors, their expression pattern suggests that they play an important role in the development and progression of this malignancy.

Study on the influence of curcumin on chemosensitivity of nephroblastoma cells

OBJECTIVE

To study the influence of curcumin on chemosensitivity of nephroblastoma cells.

METHODS

Human nephroblastoma cells line SK-NEP-1 was transplanted to the nude mice subcutaneously to establish the implantation tumor model of human nephroblastoma cells. A total of 30 tumor-bearing mice were divided into three groups of ten randomly. The routine chemotherapy group was given vincristine (0.05 mg/mL·0.2 mL/d) and actinomycin D (15 ng/mL·0.2 mL/d) combined chemotherapy regime. The curcumin chemotherapy group was given the same combined chemotherapy regimens and curcumin (30 mg/kg/d) by intraperitoneal injection. The control group was given normal saline (NS) of the same volume by intraperitoneal injection. Continuous administration would be kept for 4 weeks and 3 days a week. The volumetric changes of every group were recorded. The serum of every group in different time was collected and the VEGF content was detected by ELISA. All mice were cercrificed and the tumor tissues were stripped and weighed after 4 weeks' treatment. The tumor inhibition rate was calculated. The cell proliferation activity and apoptosis rate were detected by MTT and flow cytometry method. All data were statistically analyzed by SPSS 19.0.

RESULTS

The tumor volume, serum VEGF content, tumor inhibition rate, cell proliferation activity and apoptosis rate of routine chemotherapy group and curcumin chemotherapy group had significant differences comparing with the control group (P < 0.05) after 4-week's treatment. The cancer growth of curcumin chemotherapy group was obviously decreased and even tended to shrink comparing with routine chemotherapy group (χ(2) = 15.732, P = 0.007). The cell proliferation activity was significantly reduced and the apoptosis rate was significantly higher, (χ(2) = 9.427, P = 0.012) which showing the effect of chemotherapy was enhanced.

CONCLUSIONS

The chemosensitivity of nephroblastoma cells could be improved by curcumin, then the effect of preoperative adjuvant chemotherapy scheme would be enhanced, the growth of nephroblastoma cells would be inhibited and the surgical risk of nephroblastoma would be reduced.

Efficacy of Different Protocols in Treatment of Nephroblastoma: A revisit

BACKGROUND

Management of Nephroblastoma (NB) remains a subject of debate despite the fact that it ranked first among primary childhood's renal neoplasm. We have previously discussed this issue 13, 14, yet, the sample size was limited.

AIM

The aim of this study was to further evaluate the efficacy of initial surgery in the treatment of stage II and III pediatric NB as a part of the short administration schedule as in National Wilms' Tumor Study (NWTS)-4 and to evaluate its effectiveness compared to the long administration schedule.

PATIENTS AND METHODS

The study included 50 children who were primarily diagnosed as stage II and III NB. They were divided into 2 equal groups. Group I (n = 25) included children who have undergone neoadjuvant chemotherapy followed by surgery and postoperative chemotherapy, while group II (n = 25) included children who have undergone primary surgery as an initial management followed by chemotherapy. After a mean postoperative follow-up period of 20±6 months, clinical and radiological evaluation was performed to all patients.

RESULTS

In group I, 15 patients were preoperatively diagnosed as stage II and 10 patients as stage III while in group II, 16 patients were proved to be stage II and 9 patients were stage III. After a follow up period, clinical and radiological evaluation using CT was performed to all patients. In patients with stage II, evidence of recurrence was noted in 5 patients of group I whereas no patient showed any evidence of recurrence in group II. In patients with stage III, rebound increase in size was seen in 3 patients in group I and only one patient in group II.

CONCLUSIONS

This study confirmed our previous conclusions that initial surgical intervention with appropriate adjuvant therapy has a better outcome than the neoadjuvant chemotherapy and delayed surgery for children primarily diagnosed as stage II and III NB. Moreover, it may also act as a short administration schedule for the treatment as it is not less effective than the long administration schedule and can be administered at a substantially lower total treatment cost.

Four Cases of Spontaneous Neoplasia in the Naked Mole-Rat (Heterocephalus glaber), A Putative Cancer-Resistant Species

The naked mole-rat (Heterocephalus glaber) is widely acclaimed to be cancer-resistant and of considerable research interest based on a paucity of reports of neoplasia in this species. We have, however, encountered four spontaneous cases of neoplasia and one presumptive case of neoplasia through routine necropsy and biopsy of individuals in a zoo collection of nonhybrid naked mole-rats bred from a single pair. One case each of metastasizing hepatocellular carcinoma, nephroblastoma (Wilms' tumor), and multicentric lymphosarcoma, as well as presumptive esophageal adenocarcinoma (Barrett's esophagus-like) was identified postmortem among 37 nonautolyzed necropsy submissions of naked mole-rats over 1-year-old that were submitted for necropsy between 1998 and August 2015. One incidental case of cutaneous hemangioma was also identified antemortem by skin biopsy from one naked mole-rat examined for trauma.

[Nephroblastomas: Almost exclusively in clinical trials!]

Nephroblastomas are the most commonly occurring renal neoplasms in childhood and are treated almost exclusively in clinical trials. An important factor for further therapeutic management is the pathological evaluation of the nephrectomy specimen. Tumor stage and risk group classification are the most crucial parameters. An independent assessment of the tumor by a reference pathology center is an essential standard procedure. Although many molecular genetic discoveries have been made in nephroblastomas over recent years, molecular parameters do not (yet) play a role in treatment stratification.

Wilms tumor: Successes and challenges in management outside of cooperative clinical trials

OBJECTIVE/BACKGROUND

Management of Wilms tumor (WT) in children depends on a multidisciplinary approach to treatment, and outcomes have significantly improved as reported by cooperative group clinical trials. Here, we review the clinical outcomes of patients with WT and identify challenges and barriers encountered in multidisciplinary management outside of cooperative clinical trials.

METHODS

We retrospectively reviewed the clinical records of 35 children with WT treated between April 2002 and June 2013 at the Children's Cancer Institute in Lebanon.

RESULTS

Upfront resection was performed in 23 cases. Biopsies were performed for Stage V tumors (n=4), those with unresectable tumors or inferior vena caval thrombus (n=5), and patients who had partial surgery performed elsewhere prior to presentation (n=2). One patient died due to toxicity prior to surgery. The tumor was Stage I in eight patients, Stage II in five patients, Stages III and IV in nine patients each, and bilateral (Stage V) in four patients. Adherence to The National Wilms Tumor Study-5 recommendations was adequate. At the time of analysis, 30 patients were free of disease and four patients had relapse-all having metastatic disease initially.

CONCLUSION

The National Wilms Tumor Study-5 therapy resulted in favorable outcomes in children with nonmetastatic Wilms tumor in the setting of a multidisciplinary approach to therapy and resolution of financial barriers to medical care. Upstaging due to prior intervention and lung radiation therapy to all those with computed tomography-detected lung nodules may both have resulted in overtreatment of a subset of patients. Finally, the relatively high incidence of bilateral tumors suggests the need for further genetic and molecular studies in this patient population.

The roles of microRNAs in Wilms' tumors

Wilms' tumor is the most common renal tumor in children in which diffusely anaplastic or unfavorable histology foreshadows poor prognosis. MicroRNAs are small, non-coding RNAs that negatively regulate gene expression at the posttranscriptional level. Accumulating evidence shows that microRNA dysregulation takes part in the pathogenesis of many renal diseases, such as chronic kidney diseases, polycystic kidney disease, renal fibrosis, and renal cancers. In Wilms' tumor, dysregulation of some key oncogenic or tumor-suppressing microRNAs, such as miR-17~92 cluster, miR-185, miR-204, and miR-483, has been documented. In this review, we will summarize current evidence on the role of dysregulated microRNAs in the development of Wilms' tumor.

Intra- and interobserver variability of whole-tumour apparent diffusion coefficient measurements in nephroblastoma: a pilot study

BACKGROUND

The apparent diffusion coefficient (ADC) is potentially useful for assessing treatment response in nephroblastoma (Wilms tumour). However the precision of ADC measurements in these heterogeneous lesions is unknown.

OBJECTIVE

To assess intra- and interobserver variability of whole-tumour ADC measurements in viable parts of nephroblastomas at diagnosis and after preoperative chemotherapy.

MATERIALS AND METHODS

We included children with histopathologically proven nephroblastoma who had undergone MRI with diffusion-weighted imaging before and after preoperative chemotherapy. Three independent observers performed whole-tumour ADC measurements of all lesions, excluding non-enhancing areas. One observer evaluated all lesions on two occasions. We performed analyses using Bland-Altman plots and concordance correlation coefficient (CCC) calculations with 95% limits of agreement for median ADC, difference between pre- and post-chemotherapy median ADC (ADC shift) and percentage of pixels with ADC values <1.0 × 10(-3) mm(2)/s.

RESULTS

In 22 lesions (13 pretreatment and 9 post-treatment) in 10 children the interobserver variability in median ADC and ADC shift were within the interval of approximately ±0.1 × 10(-3) mm(2)/s (limits of agreement for median ADC ranged -0.08-0.11 × 10(-3) mm(2)/s and for ADC-shift -0.11-0.09 × 10(-3) mm(2)/s). The interobserver variability for percentage of low-ADC pixels was larger and also biased. The calculated CCC confirmed good intra- and interobserver agreement (ρ-c ranging from 0.968 to 0.996).

CONCLUSION

Measurements of whole-tumour ADC values excluding necrotic areas seem to be sufficiently precise for detection of chemotherapy-related change.

The Collaborative Wilms Tumour Africa Project; baseline evaluation of Wilms tumour treatment and outcome in eight institutes in sub-Saharan Africa

AIM

Reported survival of Wilms tumour in sub-Saharan Africa is below 50%. A published International Society of Pediatric Oncology (SIOP) Pediatric Oncology in Developing Countries (PODC) consensus adapted treatment guideline is implemented as a multi-centre prospective clinical trial at eight centres in sub-Saharan Africa. A baseline evaluation has been done to help decide on priorities to improve outcome and to assess improvements over time.

METHODS

A retrospective chart review was performed of patients admitted with Wilms tumour in the three years (2011-2013) preceding the collaborative trial. Patient outcome at the end of treatment was documented for all patients diagnosed in 2011 and 2012. Outcome was classified as (1) alive, no evidence of disease; (2) alive with disease; (3) died during treatment and (4) incomplete treatment. Details on treatment facilities, staff and estimated cost of treatment are documented.

RESULTS

Every year 114-130 patients are diagnosed. The mean survival at end of treatment is 39% (69/176) ranging from 11% to 61%. Incomplete treatment is the most common cause of treatment failure with 31% (54/176), ranging from 14% to 48% between centres. Twenty-six percent (46/176) of patients died during treatment, ranging from 13% to 37%. Estimated cost of treatment for parents ranged from 100 US$ to 1100 US$ and was considered an important cause of failure to complete treatment.

CONCLUSION

Overall two year survival is estimated at 25%. Prevention of incomplete treatment is possible and will positively affect outcome. Sharing similar local challenges in this regional collaborative project helps to identify and implement feasible, sustainable and successful strategies.

Minimally invasive nephrectomy for Wilms tumors in children - data from SIOP 2001

PURPOSE

To analyse the surgical and oncological outcome of minimally invasive surgery (MIS) for tumor nephrectomy in Wilms tumor (WT) patients.

METHODS

WT patients from the SIOP 2001 trial, undergoing MIS for tumor nephrectomy were analyzed with regard to demographic characterization, surgical specifications, complications, and outcome.

RESULTS

There were 24 children matching the inclusion criteria. Median age at operation was 40.35 months (14.3-65.4). All patients received preoperative chemotherapy. Median tumor volume was 177.5 ml at diagnosis (46.5-958) and 73.0 ml at surgery (3.8-776). There was one surgical complication (splenic injury), no intraoperative tumor rupture occurred. Abdominal stage was I in 14, II in 7, and III in 3 patients. Adequate lymph node sampling was performed in only 2 patients. One local relapse occurred. Event-free survival was 23/24, overall survival was 24/24, median follow up was 47 months (2-114).

CONCLUSIONS

We present the largest series so far of minimally invasive nephrectomies for nephroblastoma based on a multinational trial. Treatment results were comparable to those of open surgery; however, experience of operating surgeons was generally high. Discipline of lymph node sampling was inadequate. Based on this analysis a prospective study on MIS in nephroblastoma is planned by the SIOP Renal Tumor Study Group.

Feasibility of using CT volume as a predictor of specimen weight in a subgroup of patients with low risk Wilms tumors registered on COG Study AREN03B2: implications for central venous catheter placement

OBJECTIVE

Patients with stage I Wilms tumor, age ≤ 2 years, tumor ≤ 550 g may not require therapy beyond nephrectomy. This study's aims were to determine: (1) if a linear relationship exists between tumor weight and computed tomography (CT) estimated volume; (2) describe the accuracy of a slope-intercept equation in estimating weight; and (3) determine the potential impact of weight estimation on port placement decisions.

MATERIALS AND METHODS

Tumor weight and port placement information were abstracted from 105 patients, age ≤ 2 years, with tumors ± 550 g, enrolled in COG AREN03B2. One radiologist estimated tumor size from CT scan. Prolate ellipse volume (PEV) was calculated, linear regression performed, slope-intercept equation calculated, equation estimated weight determined, and potential impact of the on port placement evaluated.

RESULTS

A strong relationship exists between PEV and weight (R(2) = 0.87). The slope-intercept equation for weight was: weight = 1.04(PEV) + 58.75. Overall median relative error for the equation was 0.9%, and -3% in tumors weighing 350-750 g. Fifty-five ports were placed, 29 in patients with tumor weight ≤ 550 g, and six not placed in patients with tumor weight > 550 g.

CONCLUSIONS

The relationship between PEV and weight produced a reliable weight prediction equation. Preoperative consideration of specimen weight may diminish the number of ports placed in this population.

Evaluation of CITED1, SIX1, and CD56 protein expression for identification of blastemal elements in Wilms tumor

OBJECTIVES

Successful further treatment of Wilms tumors (WTs) after preoperative chemotherapy and surgery depends on correct histopathologic risk stratification, including quantification of remaining blastemal elements. In the present study, we assessed the usefulness of protein markers for the detection of WT blastema.

METHODS

Expression of the candidate blastemal protein markers CITED1, SIX1, and CD56 was evaluated by immunofluorescence regarding sensitivity and specificity for staining blastema in a tissue microarray containing cores from 30 WTs, a small number of rarer pediatric renal neoplasms, and normal postnatal kidney.

RESULTS

CITED1, SIX1, and CD56 were expressed in blastema in 100%, 89%, and 74%, respectively, of the WTs with this component present. However, they were also expressed in 64%, 25%, and 79%, respectively, of epithelial WT elements and 48%, 52%, and 62%, respectively, of stromal WT elements.

CONCLUSIONS

SIX1 showed the highest specificity, CITED1 the highest sensitivity, and CD56 low specificity and sensitivity for detection of postchemotherapy WT blastema. Cytokeratin staining proved to be a useful way to determine rudimentary tubular elements not readily recognized by routine staining.

Kidney protein profiling of Wilms' tumor patients by analysis of formalin-fixed paraffin-embedded tissue samples

Wilms' tumor (nephroblastoma, WT) is the most frequent renal cancer in children. However, molecular details leading to WT have not been characterized sufficiently yet. Proteomic studies might provide new insights but are hampered by limited availability of fresh frozen tissue specimen. Therefore, we tested formalin-fixed paraffin-embedded (FFPE) tissue sections routinely collected for pathological inspection for their use in in-depth-proteomic analyses of WT samples in comparison to fresh frozen specimen. The overlap of the proteins identified was over 65%. Thus we used FFPE material from 7 patients for tandem mass spectrometry based comparison of the proteomes of WT and healthy renal tissues. We detected 262 proteins, which were differentially expressed in tumor compared to healthy renal tissue. The majority of these proteins displayed lower levels in the tumor tissue and only 30% higher levels. For selected candidates data were confirmed by immunohistochemical staining. Correlation analysis of blastemal proportions in WT and protein intensities revealed candidates for tumor stratification.

CONCLUSION

This proof of principle proteomic study of FFPE tissue sections from WT patients demonstrates that these archived tissues constitute a valuable resource for larger in-depth proteomic studies to identify markers to follow chemotherapy efficiency or for stratification of tumor subtypes.