Bilateral Wilms tumor with anaplasia: A report from the Children's Oncology Group Study AREN0534

INTRODUCTION

The purpose of this study is to examine the outcomes in children with anaplastic bilateral Wilms tumor (BWT) from study AREN0534 in order to define potential prognostic factors and areas to target in future clinical trials.

METHODS

Demographic and clinical data from AREN0534 study patients with anaplasia (focal anaplasia [FA], or diffuse anaplasia [DA]) were compared. Event-free survival (EFS) and overall survival (OS) were reported using Kaplan-Meier estimation with 95% confidence bands, and differences in outcomes between FA and DA compared using log-rank tests. The impact of margin status was analyzed.

RESULTS

Twenty-seven children who enrolled on AREN0534 had evidence of anaplasia (17 DA, 10 FA) in at least one kidney and were included in this analysis. Twenty-six (96%) had BWT. Nineteen percent had anaplastic histology in both kidneys (four of 17 DA, and one of 10 FA). Forty-six percent with BWT had bilateral nephron-sparing surgery (NSS); one child who went off protocol therapy, eventually required bilateral completion nephrectomies. Median follow-up for EFS and OS was 8.6 and 8.7 years from enrollment. Four- and 8-year EFS was 53% [95% confidence interval (CI): 34%-83%] for DA; 4-year EFS was 80% [95% CI: 59%-100%], and 8-year EFS 70% [95% CI: 47%-100%] for FA. Three out of 10 children with FA and eight out of 17 children with DA had events. EFS did not differ statistically by margin status (p = .79; HR = 0.88). Among the six children who died (five DA, one FA), all experienced prior relapse or progression within 18 months.

CONCLUSION

Events in children with DA/FA in the setting of BWT occurred early. Caution should be taken about interpreting the impact of margin status outcomes in the context of contemporary multimodal therapy. Future targeted investigations in children with BWT and DA/FA are needed.

Update on cancer predisposition syndromes and surveillance guidelines for childhood brain tumors

Tumors of the central nervous system (CNS) comprise the second most common group of neoplasms in childhood. The incidence of germline predisposition among children with brain tumors continues to grow as our knowledge on disease aetiology increases. Some children with brain tumors may present with non-malignant phenotypic features of specific syndromes (e.g. nevoid basal cell carcinoma syndrome, neurofibromatosis type 1 and type 2, DICER1 syndrome, and constitutional mismatch repair deficiency), while others may present with a strong family history of cancer (e.g. Li-Fraumeni syndrome), or with a rare tumor commonly found in the context of germline predisposition (e.g. rhabdoid tumor predisposition syndrome). Approximately 50% of patients with a brain tumor may be the first in a family identified to have a predisposition. The past decade has witnessed a rapid expansion in our molecular understanding of CNS tumors. A significant proportion of CNS tumors are now well characterized and known to harbor specific genetic changes that can be found in the germline. Additional novel predisposition syndromes are also being described. Identification of these germline syndromes in individual patients has not only enabled cascade testing of family members and early tumor surveillance but increasingly has also impacted cancer management in those patients. Therefore, the AACR Cancer Predisposition Working Group chose to highlight these advances in CNS tumor predisposition and summarize and/or generate surveillance recommendations for established and more recently emerging pediatric brain tumor predisposition syndromes.

Hallmark discoveries in the biology of Wilms tumour

The modern study of Wilms tumour was prompted nearly 50 years ago, when Alfred Knudson proposed the 'two-hit' model of tumour development. Since then, the efforts of researchers worldwide have substantially expanded our knowledge of Wilms tumour biology, including major advances in genetics - from cloning the first Wilms tumour gene to high-throughput studies that have revealed the genetic landscape of this tumour. These discoveries improve understanding of the embryonal origin of Wilms tumour, familial occurrences and associated syndromic conditions. Many efforts have been made to find and clinically apply prognostic biomarkers to Wilms tumour, for which outcomes are generally favourable, but treatment of some affected individuals remains challenging. Challenges are also posed by the intratumoural heterogeneity of biomarkers. Furthermore, preclinical models of Wilms tumour, from cell lines to organoid cultures, have evolved. Despite these many achievements, much still remains to be discovered: further molecular understanding of relapse in Wilms tumour and of the multiple origins of bilateral Wilms tumour are two examples of areas under active investigation. International collaboration, especially when large tumour series are required to obtain robust data, will help to answer some of the remaining unresolved questions.

Genetic and epigenetic features of bilateral Wilms tumor predisposition in patients from the Children's Oncology Group AREN18B5-Q

Developing synchronous bilateral Wilms tumor suggests an underlying (epi)genetic predisposition. Here, we evaluate this predisposition in 68 patients using whole exome or genome sequencing (n = 85 tumors from 61 patients with matched germline blood DNA), RNA-seq (n = 99 tumors), and DNA methylation analysis (n = 61 peripheral blood, n = 29 non-diseased kidney, n = 99 tumors). We determine the predominant events for bilateral Wilms tumor predisposition: 1)pre-zygotic germline genetic variants readily detectable in blood DNA [WT1 (14.8%), NYNRIN (6.6%), TRIM28 (5%), and BRCA-related genes (5%)] or 2)post-zygotic epigenetic hypermethylation at 11p15.5 H19/ICR1 that may require analysis of multiple tissue types for diagnosis. Of 99 total tumor specimens, 16 (16.1%) have 11p15.5 normal retention of imprinting, 25 (25.2%) have 11p15.5 copy neutral loss of heterozygosity, and 58 (58.6%) have 11p15.5 H19/ICR1 epigenetic hypermethylation (loss of imprinting). Here, we ascertain the epigenetic and genetic modes of bilateral Wilms tumor predisposition.

Multiple Germline Events Contribute to Cancer Development in Patients with Li-Fraumeni Syndrome

Li-Fraumeni syndrome (LFS) is an autosomal dominant cancer-predisposition disorder. Approximately 70% of individuals who fit the clinical definition of LFS harbor a pathogenic germline variant in the TP53 tumor suppressor gene. However, the remaining 30% of patients lack a TP53 variant and even among variant TP53 carriers, approximately 20% remain cancer-free. Understanding the variable cancer penetrance and phenotypic variability in LFS is critical to developing rational approaches to accurate, early tumor detection and risk-reduction strategies. We leveraged family-based whole-genome sequencing and DNA methylation to evaluate the germline genomes of a large, multi-institutional cohort of patients with LFS (n = 396) with variant (n = 374) or wildtype TP53 (n = 22). We identified alternative cancer-associated genetic aberrations in 8/14 wildtype TP53 carriers who developed cancer. Among variant TP53 carriers, 19/49 who developed cancer harbored a pathogenic variant in another cancer gene. Modifier variants in the WNT signaling pathway were associated with decreased cancer incidence. Furthermore, we leveraged the noncoding genome and methylome to identify inherited epimutations in genes including ASXL1, ETV6, and LEF1 that confer increased cancer risk. Using these epimutations, we built a machine learning model that can predict cancer risk in patients with LFS with an area under the receiver operator characteristic curve (AUROC) of 0.725 (0.633-0.810).

Significance

Our study clarifies the genomic basis for the phenotypic variability in LFS and highlights the immense benefits of expanding genetic and epigenetic testing of patients with LFS beyond TP53. More broadly, it necessitates the dissociation of hereditary cancer syndromes as single gene disorders and emphasizes the importance of understanding these diseases in a holistic manner as opposed to through the lens of a single gene.

The Genetic and Epigenetic Features of Bilateral Wilms Tumor Predisposition: A Report from the Children's Oncology Group AREN18B5-Q Study

This study comprehensively evaluated the landscape of genetic and epigenetic events that predispose to synchronous bilateral Wilms tumor (BWT). We performed whole exome or whole genome sequencing, total-strand RNA-seq, and DNA methylation analysis using germline and/or tumor samples from 68 patients with BWT from St. Jude Children's Research Hospital and the Children's Oncology Group. We found that 25/61 (41%) of patients evaluated harbored pathogenic or likely pathogenic germline variants, with WT1 (14.8%), NYNRIN (6.6%), TRIM28 (5%) and the BRCA-related genes (5%) BRCA1, BRCA2, and PALB2 being most common. Germline WT1 variants were strongly associated with somatic paternal uniparental disomy encompassing the 11p15.5 and 11p13/WT1 loci and subsequent acquired pathogenic CTNNB1 variants. Somatic coding variants or genome-wide copy number alterations were almost never shared between paired synchronous BWT, suggesting that the acquisition of independent somatic variants leads to tumor formation in the context of germline or early embryonic, post-zygotic initiating events. In contrast, 11p15.5 status (loss of heterozygosity, loss or retention of imprinting) was shared among paired synchronous BWT in all but one case. The predominant molecular events for BWT predisposition include pathogenic germline variants or post-zygotic epigenetic hypermethylation at the 11p15.5 H19/ICR1 locus (loss of imprinting). This study demonstrates that post-zygotic somatic mosaicism for 11p15.5 hypermethylation/loss of imprinting is the single most common initiating molecular event predisposing to BWT. Evidence of somatic mosaicism for 11p15.5 loss of imprinting was detected in leukocytes of a cohort of BWT patients and long-term survivors, but not in unilateral Wilms tumor patients and long-term survivors or controls, further supporting the hypothesis that post-zygotic 11p15.5 alterations occurred in the mesoderm of patients who go on to develop BWT. Due to the preponderance of BWT patients with demonstrable germline or early embryonic tumor predisposition, BWT exhibits a unique biology when compared to unilateral Wilms tumor and therefore warrants continued refinement of its own treatment-relevant biomarkers which in turn may inform directed treatment strategies in the future.

Nephron-sparing surgery for renal cell carcinoma in children and young adults: A systematic review

OBJECTIVE

To determine the patient characteristics and role of nephron-sparing surgery (NSS) in the treatment of children and young adults with renal cell carcinoma (RCC).

METHODS

A systematic search of Embase, MEDLINE, and Scopus databases was conducted in December 2021 according to Cochrane collaboration recommendations. All included manuscripts were assessed for patient characteristics and all reported outcomes for patients undergoing partial nephrectomy (PN), and radical nephrectomy (RN) outcomes were abstracted as a comparison group. Primary outcomes included surgical outcomes, overall survival, kidney outcomes. Outcomes were pooled with weighted mean and ranges. Meta-analysis was not performed given study quality. This systematic review was prospectively registered on PROSPERO (CRD42022300261).

RESULTS

We found a total of 16 studies describing 119 and 559 unique patients undergoing PN and RN, respectively, with a mean age of 12.2 years and mean follow-up of 59.1 months. The mean tumor size for patients undergoing PN was 3.5 cm. Of the 113 patients undergoing PN with available data, 109 were alive at follow-up (98%). No studies reported long-term kidney outcomes, and four studies reported surgical outcomes. All studies had at least moderate risk of bias.

CONCLUSIONS

The use of NSS in children and young adults with RCC is feasible in selected patients. However, small sample sizes, confounding, and low study quality limit clinical recommendation on NSS in this population. There are significant opportunities for future research on the use of NSS in RCC, especially with systematic reporting of oncological, kidney, and surgical outcomes.

Outcomes according to treatment using an established protocol in patients with bilateral Wilms' tumor: A national Canadian population-based study

BACKGROUND

Bilateral Wilms tumor (BWT) is a rare entity. The goal of this study is to report outcomes (overall and event-free survival, OS/EFS) of BWT in a large cohort representative of the Canadian population since 2000. We focused on the occurrence of late events (relapse or death beyond 18 months), as well as outcomes of patients treated following the only protocol specifically designed for BWT to date, AREN0534, compared to patients treated following other therapeutic schemes.

METHODS

Data was obtained for patients diagnosed with BWT between 2001 and 2018 from the Cancer in Young People in Canada (CYP-C) database. Demographics, treatment protocols, and dates for events were collected. Specifically, we examined outcomes of patients treated according to the Children's Oncology Group (COG) protocol AREN0534 since 2009. Survival analysis was performed.

RESULTS

57/816 (7%) of patients with Wilms tumor had BWT during the study period. Median age at diagnosis was 2.74 years (IQR 1.37-4.48) and 35 (64%) were female; 8/57 (15%) had metastatic disease. After a median follow-up of 4.8 years (IQR 2.8-5.7 years, range 0.2-18 years), OS and EFS were 86% (CI 73-93%) and 80% (CI 66-89%), respectively. Less than 5 events were recorded after 18 months from diagnosis. Since 2009, patients treated according to the AREN0534 protocol had a statistically significant higher OS compared to patients treated with other protocols.

CONCLUSIONS

In this large Canadian cohort of patients with BWT, OS and EFS compared favorably to the published literature. Late events were rare. Patients treated according to a disease-specific protocol (AREN0534) had improved overall survival.

TYPE OF STUDY

Original article.

LEVEL OF EVIDENCE

Level IV.

Abstract B027: The development of a multiscale transcriptional atlas of sarcoma

Objectives: Sarcomas are mesodermal cancers of bone and soft tissue of which there are >60 malignant varieties, many of which can be difficult to diagnose or subtype using traditional histopathology. A universal molecular definition of sarcoma types would therefore be an invaluable tool to the diagnostic pathologist. RNA has the potential to offer a complimentary perspective to cytogenetic- and methylation-based diagnostics, as it represents the active state of the disease at sampling and better reveals its phenotype. Recognizing the potential for RNA-based classification, we set out to create a first-generation transcriptional atlas of sarcoma. Methods: To develop transcriptional definitions of cancers with the potential to further subclassify tumor types, we designed a self-optimizing and scale-adaptive unsupervised method (RACCOON), which groups samples into hierarchically organized clusters. We used this approach on the UCSC Treehouse Childhood Cancer Compendium, a set of 2,178 pediatric and 9,400 adult tumors, 1,130 of which are sarcomas, as well as 1,735 non-neoplastic samples. We then trained an ensemble of convolutional neural networks to classify tumors to these transcriptional clusters. We have now added 624 more sarcoma samples from Toronto centers and international collaborators to better represent the breadth of sarcoma. We are actively sequencing 500 additional samples in partnership with the Gabriella Miller Kids First Research Program to yield an expanded cohort of >2,200 uniformly processed and analyzed sarcomas. Results: Sarcomas organize into two clusters at the highest hierarchical level: one characterized by entities which occur primarily in adults and resemble mature tissue, the other by primarily pediatric entities which exhibit high stemness and resemble embryonic tissue. Several included entities are not bona fide sarcomas but originate from the mesoderm (e.g., Wilms Tumor) signifying a common transcriptional identity for mesodermal neoplasms. Additionally, we demonstrate the first transcriptional subtypes of central osteosarcoma reflecting its major histotypes and representing divergent clinical courses. We also determine Ewing Sarcoma (ES) to be a distinct entity which clusters separately from all other cancers, raising questions of its origin and affinity to sarcoma. When classifying ongoing patients to the atlas, we correctly classified >85% of tumors and corrected the diagnosis of 7%. We find 14% of ES in our dataset were likely misdiagnosed CIC- or BCOR-driven sarcomas. Critically, assigned subtypes are consistent between primary and relapse pairs. Conclusion: RNA-seq is a promising tool for both subtype discovery and classifying sarcoma in ongoing patients. We have already included this tool in tumor boards to help inform patient care. Our method reveals the overarching organization of sarcoma for the first time and specifies its underlying biology. This atlas is ever-growing and is open to the community to contribute.

Citation Format: Joshua O. Nash, Federico Comitani, Rose Chami, Sarah Cohen-Gogo, Astra Chang-Schwertschkow, Yael Babichev, Jodi Lees, Noa Alon, Nalan Gokgoz, Stephen Man Yu, Kyoko Yuki, Miranda Lorenti, Zhanqin Liu, Alaina McGoey, Famida Spatare, Bernarld Castro, Kim Tsoi, Hagit Peretz Soroka, Jack Brzezinski, Anita Villani, Albiruni Razak, Abha Gupta, Elizabeth Demicco, Gino Somers, Brendan C. Dickson, Jay S. Wunder, Irene L. Andrulis, David Malkin, Rebecca A. Gladdy, Adam Shlien. The development of a multiscale transcriptional atlas of sarcoma [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr B027.

The pathophysiology of bilateral and multifocal Wilms tumors: What we can learn from the study of predisposition syndromes

Approximately 5% of patients with Wilms tumor present with synchronous bilateral disease. The development of synchronous bilateral Wilms tumor (BWT) is highly suggestive of a genetic or epigenetic predisposition. Patients with known germline predisposition to Wilms tumor (WT1 variants, Beckwith Wiedemann spectrum, TRIM28 variants) have a higher incidence of BWT. This Children's Oncology Group (COG)-International Society for Pediatric Oncology (SIOP-) HARMONICA initiative review for pediatric renal tumors details germline genetic and epigenetic predisposition to BWT development, with an emphasis on alterations in 11p15.5 (ICR1 gain of methylation, paternal uniparental disomy, and postzygotic somatic mosaicism), WT1, TRIM28, and REST. Molecular mechanisms that result in BWT are often also present in multifocal Wilms tumor (multiple separate tumors in one or both kidneys). We identify priority areas for international collaborative research to better understand how predisposing genetic or epigenetic factors associate with response to neoadjuvant chemotherapy, oncologic outcomes, and long-term renal function outcomes.

Abstract 3755: DNA methylation patterns, but not genetic sequence alterations, are concordant across multiply sampled sites within individuals with unilateral and bilateral Wilms tumors

Wilms tumor, the most common renal malignancy of childhood, is a disease marked by heterogeneity. One tumor can harbor multiple histologic subtypes and multifocal or bilateral disease is common occurring in up to 10% of patients. Several molecular features have been associated with Wilms tumors and some are used for risk stratification. However, it is unclear which, if any, features are consistent throughout a single tumor or shared between tumors in cases of bilateral disease. To answer this question, we generated genomic and epigenomic data from multiply sampled Wilms tumors from 10 patients - 3 with unilateral disease and 7 with bilateral disease. Multiple samples from each tumor as well as matched normal tissues were included when available. All tumors and matched normal tissues had DNA methylation array data available. Segmental chromosomal aberrations (SCAs) were inferred from methylation array data. Sequencing data were available for all bilateral patients but not for unilateral patients. We found that SCAs were discordant both between pairs of bilateral tumors and within multiply sampled unilateral tumors. This discordance included SCAs used for clinical risk stratification (chromosome 1q gain, 1p loss). Sequence variants were also rarely shared between pairs of bilateral tumors. On the other hand, DNA methylation patterns were concordant across all samples for each individual. We previously described 3 distinct DNA methylation patterns in Wilms tumors and found that all samples from each patient classified into the same subgroup. Furthermore, DNA methylation at Wilms tumor-specific and subgroup-specific differentially methylated regions had high (>0.8) correlation in all samples from all cases. Our data demonstrate that, in contrast to genomic changes such as SCAs and sequence alterations, DNA methylation patterns in Wilms tumors are frequently shared between paired tumors in bilateral disease and in multiple regions within individual tumors. This is consistent with earlier studies demonstrating that gain of methylation at the H19 imprinted region is often the earliest event in Wilms tumors and in some cases likely occurs in the embryonic intermediate mesoderm prior to the development of individual kidneys. Our findings demonstrate the utility of Wilms tumor DNA methylation patterns in overcoming tumor heterogeneity for risk stratification in cases of bilateral or multifocal Wilms tumors.

Citation Format: Jack Brzezinski, Sanaa Choufani, Cheryl Shuman, Rodrigo Romao, Armando Lorenzo, Rosanna Weksberg. DNA methylation patterns, but not genetic sequence alterations, are concordant across multiply sampled sites within individuals with unilateral and bilateral Wilms tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3755.

Late Kidney Effects of Nephron-Sparing vs Radical Nephrectomy for Wilms Tumor: A Systematic Review and Meta-Analysis

PURPOSE

We compare differences in long-term kidney function between patients undergoing either radical nephrectomy (RN) or nephron-sparing surgery (NSS) in unilateral and bilateral Wilms tumor (WT), respectively.

MATERIALS AND METHODS

A systematic search was performed in September 2020. Comparative studies were evaluated according to Cochrane collaboration recommendations. Assessed long-term (>1-year postoperative) outcomes included chronic kidney disease, hypertension and glomerular filtration rate, among others. Odds ratio and mean difference with 95% confidence interval were extrapolated from available data for quantitative synthesis. Random-effects meta-analysis and meta-regression were performed according to study design and techniques. The systematic review was prospectively registered on PROSPERO (CRD42020205378).

RESULTS

A total of 23 studies describing 293 cases of unilateral WT and 386 cases of bilateral WT were included in the qualitative synthesis. Overall effect estimates demonstrate that patients undergoing RN have significantly increased odds of developing abnormal kidney function (OR 4.29, 95% CI 1.02, 18.00) and lower estimated glomerular filtration rate at long-term followup (mean difference -8.99, 95% CI -16.40, -1.58) compared to those undergoing NSS. In bilateral WT, patients undergoing RN with contralateral NSS have higher odds of developing abnormal kidney function (OR 3.82, 95% CI 1.76, 8.33) and hypertension (OR 5.81, 95% CI 1.31, 25.68) compared to bilateral NSS.

CONCLUSIONS

Current evidence is low quality but suggests that NSS for unilateral and bilateral WT may be associated with better kidney function or blood pressure at late followup. Further research to investigate sources of heterogeneity is recommended.

Clinically and biologically relevant subgroups of Wilms tumour defined by genomic and epigenomic analyses

Background

Although cure rates for Wilms tumours (WT) are high, many patients receive therapy with attendant long-term complications. Our goal was to stratify WT using genome-wide analyses to identify candidate molecular features for patients who would benefit from a reduction in therapy.

Methods

We generated DNA methylation and exome sequencing data on WT–kidney pairs (n = 57) and unpaired tumours (n = 27) collected either at our centre or by the Children’s Oncology Group. Samples were divided into a discovery set (n = 32) and validation set (n = 52).

Results

Analysis of DNA methylation revealed two subgroups of WT with distinct features. Subgroup A has a similar DNA methylation profile to mature kidney, while Subgroup B has genome-wide dysregulation of DNA methylation. The rate of non-synonymous missense mutations and segmental chromosomal aberrations was higher in Subgroup B tumours, suggesting that this group has genome instability related to its epigenetic state. Subgroup A had a higher proportion of cases of bilateral disease. Tumours with high-risk histology or from patients who relapsed were only found in Subgroup B.

Conclusion

We have identified subgroup-specific molecular events that could inform future work supporting more targeted therapeutic approaches and patient stratification. We propose a novel developmental tumour model based on these findings.

Electron Capture Gas-Liquid Chromatographic Determination of Methyl Mercury in Fish and Shellfish: Collaborative Study

A method for determining methyl mercury in fish and shellfish was collaboratively studied in 8 laboratories. Methyl mercury is isolated from acetonewashed, homogenized tissue by adding hydrochloric acid and extracting into benzene the methyl mercuric chloride that is formed. The benzene extract is concentrated and analyzed for methyl mercuric chloride by electron capture gas-liquid chromatography on 5% DEGS-PS treated with inorganic mercuric chloride solution. The quantitation limit for the method is 0.05 μg Hg/g. Each collaborator determined methyl mercury at 2 levels in blind duplicate samples of swordfish, tuna, oyster, and shrimp tissues. Both fortified and unfortified samples were analyzed. Methyl-bound mercury in the samples ranged from 0.15 to 148 μg Hg/g. The reproducibility coefficients of variation for the 8 samples ranged from 3 to 13%. The accuracy, measured by comparison to reference values, ranged from 99 to 120%. Reference values were determined in the Associate Referee's laboratory by replicate analyses of the fortified and unfortified samples. The method has been adopted official first action.

Volumetric assessment of unaffected parenchyma and Wilms' tumours: analysis of response to chemotherapy and surgery using a semi-automated segmentation algorithm in children with renal neoplasms

OBJECTIVE

To present our proof of concept with semi-automatic image recognition/segmentation technology for calculation of tumour/parenchyma volume.

METHODS

We reviewed Wilms' tumours (WTs) between 2000 and 2018, capturing computed tomography images at baseline, after neoadjuvant chemotherapy (NaC) and postoperatively. Images were uploaded into MATLAB-3-D volumetric image processing software. The program was trained by two clinicians who supervised the demarcation of tumour and parenchyma, followed by automatic recognition and delineation of tumour margins on serial imaging, and differentiation from uninvolved renal parenchyma. Volume was automatically calculated for both.

RESULTS

During the study period, 98 patients were identified. Of these, based on image quality and availability, 32 (38 affected moieties) were selected. Most patients (65%) were girls, diagnosed at age 50 ± 37 months of age. NaC was employed in 64% of patients. Surgical management included 27 radical and 11 partial nephrectomies. Automated volume assessment demonstrated objective response to NaC for unilateral and bilateral tumours (68 ± 20% and 53 ± 39%, respectively), as well as preservation on uninvolved parenchyma with partial nephrectomy (70 ± 46 cm³ at presentation to 57 ± 41 cm³ post-surgery).

CONCLUSION

Volumetric analysis is feasible and allows objective assessment of tumour and parenchyma volume in response to chemotherapy and surgery. Our data show changes after therapy that may be otherwise difficult to quantify. Use of such technology may improve surgical planning and quantification of response to treatment, as well as serving as a tool to predict renal reserve and long-term changes in renal function.

Tumor risk and surveillance for children with hereditary disorders affecting growth

PURPOSE OF REVIEW

Hereditary disorders affecting growth (both overgrowth and growth retardation) are frequently associated with heightened risk of neoplastic disease. This review summarizes the tumor spectra associated with these conditions and identifies disease-specific screening approaches.

RECENT FINDINGS

An understanding of the molecular events underlying many of these growth disorders has evolved significantly over the past several years. Recognition of genotype-phenotype associations, in many cases, informs the cancer risk profile. Additionally, accumulating data suggest a benefit of rational presymptomatic surveillance for at-risk individuals, with a reduction in tumor-associated morbidity. Recent clinical practice recommendations have established risk-driven paradigms for tumor surveillance in the context of hereditary tumor predisposition syndromes, including those affecting growth.

SUMMARY

Clinicians caring for children with growth disorders should be aware of syndromic associations and the associated cancer risks. Knowledge of tumor spectra and recommended surveillance strategies may facilitate tumor diagnosis at an early stage and reduce morbidity of the disease and associated treatments.

Ultrasound imaging for lumbar punctures and epidural catheterisations: systematic review and meta-analysis

OBJECTIVE

To determine whether ultrasound imaging can reduce the risk of failed lumbar punctures or epidural catheterisations, when compared with standard palpation methods, and whether ultrasound imaging can reduce traumatic procedures, insertion attempts, and needle redirections.

DESIGN

Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES

Ovid Medline, Embase, and Cochrane Central Register of Controlled Trials up to May 2012, without restriction by language or publication status.

REVIEW METHODS

Randomised trials that compared ultrasound imaging with standard methods (no imaging) in the performance of a lumbar puncture or epidural catheterisation were identified.

RESULTS

14 studies with a total of 1334 patients were included (674 patients assigned to the ultrasound group, 660 to the control group). Five studies evaluated lumbar punctures and nine evaluated epidural catheterisations. Six of 624 procedures conducted in the ultrasound group failed; 44 of 610 procedures in the control group failed. Ultrasound imaging reduced the risk of failed procedures (risk ratio 0.21 (95% confidence interval 0.10 to 0.43), P<0.001). Risk reduction was similar when subgroup analysis was performed for lumbar punctures (risk ratio 0.19 (0.07 to 0.56), P=0.002) or epidural catheterisations (0.23 (0.09 to 0.60), P=0.003). Ultrasound imaging also significantly reduced the risk of traumatic procedures (risk ratio 0.27 (0.11 to 0.67), P=0.005), the number of insertion attempts (mean difference -0.44 (-0.64 to -0.24), P<0.001), and the number of needle redirections (mean difference -1.00 (-1.24 to -0.75), P<0.001).

CONCLUSIONS

Ultrasound imaging can reduce the risk of failed or traumatic lumbar punctures and epidural catheterisations, as well as the number of needle insertions and redirections. Ultrasound may be a useful adjunct for these procedures.

Severe severe psychological repulsion reaction in patient with PAD resulted in natural lower extremity mummification

This case report describes the very uncommon event of mummification of the lower limb occurring naturally in a patient with peripheral arterial occlusive disease aggravated by severe reactive aversion and serves as a warning that this can happen in cases of untreated advanced critical limb ischemia even in well developed countries.

Reaction efficiency of diffusion-controlled processes on finite, planar arrays. II. Crystal surfaces

We consider 36 planar nets identified by O'Keeffe and Hyde and calculate for each, using the theory of finite Markovian processes, the overall mean walk length n (first passage time) of a reactant diffusing randomly on a finite platelet before being trapped at a reaction center; the results are analyzed in terms of the total number N of lattice sites, the number N(b) of boundary sites, the average valence nu, and the bond orientation function Psi. We establish that crystalline platelets that are members of the same compatible class are characterized by very comparable catalytic efficiencies. The results obtained are also linked to an analysis of the kinetics of docking in postnucleation stages of protein self-assembly and to a recent conjecture on the symmetries of planar nets and the hard disk freezing transition.

Tunable electrogenerated chemiluminescence from CdSe nanocrystals

Electrochemical behavior and related optoelectronic properties of CdSe nanocrystals (NCs) in aprotic solutions have been investigated. NCs of 2.50 ± 0.50 nm diameter were synthesized using a modified procedure in which the temperatures at the time of Se precursor injection and NC growth were controlled. The electrochemical band gap was found to agree with those determined by UV–vis absorption spectroscopy and by the tunneling current-voltage spectrum in the literature. Electrogenerated chemiluminescence of the NCs with peak maxima at 1.90 eV (red, 653 nm) and 2.55 eV (blue, 486 nm) can be generated and altered by scanning the voltage between –1.60 and –1.80 V and between –2.00 and –2.20 V, respectively. The results demonstrate the potential capability of the NCs for light emission tuned by the applied potential.Key words: CdSe nanocrystals, electrochemistry, electrogenerated chemiluminescence, UV–vis spectroscopy, photoluminescence.

A conjecture concerning the symmetries of planar nets and the hard disk freezing transition

We examine the conjecture that in a 2D system of hard disks the packing fraction at which the continuous transition from the ordered 2D solid to the hexatic phase occurs, and that at which the very weak first-order or continuous transition from the hexatic to the fluid phase occurs, can be correlated with the packing fractions of patterned networks (tessellations) of disk positions that span the 2D space. We identify three tessellations that have less than close packed density, span 2D space, and have percolated continuity of disk-disk contact. One has a packing fraction of eta = 0.729, very slightly larger than the estimated packing fraction at the ordered solid-to-hexatic transition, eta = 0.723, and the other two have packing fractions of approximately 0.680, slightly smaller than that identified as the upper end of the stability range of the liquid phase, eta = 0.699. The region 0.680 < eta < 0.729 is identified with the hexatic domain. The end points of this region can be placed in correspondence with nets for which the defining unit structures are regular polygons, but not the hexatic domain, in which there are randomly dispersed clusters that need not be regular polygons. The densities at which the percolated tessellations span the 2D space are regarded as special points along the density axis. We suggest that the possibility of forming different symmetry nets with sensibly the same packing fraction is a geometric analogue of a bifurcation condition that divides the configuration space into qualitatively different domains, and that the onset and end of the hexatic region are correlated with such divisions of the configuration space.

Elevating tensor rank increases anisotropy in brain areas associated with intra-voxel orientational heterogeneity (IVOH): a generalised DTI (GDTI) study

Rank-2 tensors are unable to represent multi-modal diffusion associated with intra-voxel orientational heterogeneity (IVOH), which occurs where axons are incoherently oriented, such as where bundles intersect or diverge. Under this condition, they are oblate or spheroidally shaped, resulting in artefactually low anisotropy, potentially masking reduced axonal density, myelinisation and integrity. Higher rank tensors can represent multi-modal diffusion, and suitable metrics such as generalised anisotropy (GA) and scaled entropy (SE) have been introduced. The effect of tensor rank was studied through simulations, and analysing high angular resolution diffusion imaging (HARDI) data from two volunteers, fit with rank-2, rank-4 and rank-6 tensors. The variation of GA and SE as a function of rank was investigated through difference maps and region of interest (ROI)-based comparisons. Results were correlated with orientation distribution functions (ODF) reconstructed with q-ball, and with colour-maps of the principal and second eigenvectors. Simulations revealed that rank-4 tensors are able to represent multi-modal diffusion, and that increasing rank further has a minor effect on measurements. IVOH was detected in subcortical regions of the corona radiata, along the superior longitudinal fasciculus, in the radiations of the genu of the corpus callosum, in peritrigonal white matter and along the inferior fronto-occipital and longitudinal fascicula. In these regions, elevating tensor rank increased anisotropy. This was also true for the corpus callosum, cingulum and anterior limb of the internal capsule, where increasing tensor rank resulted in patterns that, although mono-modal, were more anisotropic. In these regions the second eigenvector was coherently oriented. As rank-4 tensors have only 15 distinct elements, they can be determined without acquiring a large number of directions. By removing artefactual underestimation of anisotropy, their use may increase the sensitivity to pathological change.

Excretion and peripheral metabolism of 1, 2-3H-testosterone and androgens in rats following intoxication with organophosphorous insecticides. 1--Acute exposure

The effects of methylbromphenvinfos (MBFV) and fenitrothion on androgen levels, excretion and peripheral metabolism were studied in male rats. The insecticides were administered orally in high, single doses. Plasma testosterone levels and urinary excretion of 11-deoxy-17-ketosteroids had increased 24 and 48 h after MBVF administration. During the same time period, fenitrothion reduced plasma and urine androgens, but after 72 h significant increases in steroid levels and excretion were apparent. Investigation of the peripheral metabolism of 3H-testosterone indicated that fenitrothion markedly diminished the urinary excretion of 3H-androstenedione during the first 48 h and then increased its level after 72 h. Simultaneously, 3H-testosterone elimination was increased during the first 24-48 h and then decreased after 72 h. These data suggest that MBFV and fenithrothion in high doses can produce significant alteration in physiological hormonal balance of the male reproductive system.

Posttraumatic hematoma beneath the epineurium of a branch of the median nerve. Case report

A very rare case of a posttraumatic hematoma, localized beneath the epineurium of a branch of the median nerve, is described and a probable mechanism of its development if given. Full recovery of nerve function followed surgery.

Mean carbon dioxide tension in the brain after carbonic anhydrase inhibition

1. Measurements of the CO(2) tensions in arterial blood, in blood from the superior sagittal sinus, in cisternal cerebrospinal fluid, and on the surface of the cerebral cortex were made in spontaneously breathing anaesthetized cats and rats after inhibition of carbonic anhydrase with acetazolamide in doses of 50-150 mg/kg.2. After an acetazolamide dose of 50 mg/kg in cats there was a mean increase in the c.s.f. CO(2) tension of 8 mm Hg; after a dose of 100 mg/kg the corresponding mean increase was 13 mm Hg.3. Since the CO(2) tension measured in venous blood was only moderately influenced by the acetazolamide, the normal P(CO2) difference between venous blood and c.s.f. was markedly reduced. The apparent arterial CO(2) tension, i.e. the CO(2) tension measured in vitro, always changed to the same extent as the c.s.f. CO(2) tension.4. The findings were confirmed by measurements of the CO(2) tension on the surface of the cerebral cortex, and by measurements of the blood and c.s.f. CO(2) tensions in the rat.5. It is concluded that the mean tissue CO(2) tension of the brain can be estimated from the measured arterial CO(2) tension, even under conditions of carbonic anhydrase inhibition.