BRD4 isoforms have distinct roles in tumour progression and metastasis in rhabdomyosarcoma.

BRD4, a bromodomain and extraterminal (BET) protein, is deregulated in multiple cancers and has emerged as a promising drug target. However, the function of the two main BRD4 isoforms (BRD4-L and BRD4-S) has not been analysed in parallel in most cancers. This complicates determining therapeutic efficacy of pan-BET inhibitors. In this study, using functional and transcriptomic analysis, we show that BRD-L and BRD4-S isoforms play distinct roles in fusion negative embryonal rhabdomyosarcoma. BRD4-L has an oncogenic role and inhibits myogenic differentiation, at least in part, by activating myostatin expression. Depletion of BRD4-L in vivo impairs tumour progression but does not impact metastasis. On the other hand, depletion of BRD4-S has no significant impact on tumour growth, but strikingly promotes metastasis in vivo. Interestingly, BRD4-S loss results in the enrichment of BRD4-L and RNA Polymerase II at integrin gene promoters resulting in their activation. In fusion positive alveolar rhabdomyosarcoma, BRD4-L is unrestricted in its oncogenic role, with no evident involvement of BRD4-S. Our work unveils isoform-specific functions of BRD4 in rhabdomyosarcoma.

Histone variant H3.3 promotes metastasis in alveolar rhabdomyosarcoma.

The relatively quiet mutational landscape of rhabdomyosarcoma (RMS) suggests that epigenetic deregulation could be central to oncogenesis and tumour aggressiveness. Histone variants have long been recognised as important epigenetic regulators of gene expression. However, the role of histone variants in RMS has not been studied hitherto. In this study, we show that histone variant H3.3 is overexpressed in alveolar RMS (ARMS), an aggressive subtype of RMS. Functionally, knockdown of H3F3A, which encodes for H3.3, significantly impairs the ability of ARMS cells to undertake migration and invasion and reduces Rho activation. In addition, a striking reduction in metastatic tumour burden and improved survival is apparent in vivo. Using RNA-sequencing and ChIP-sequencing analyses, we identified melanoma cell adhesion molecule (MCAM/CD146) as a direct downstream target of H3.3. Loss of H3.3 resulted in a reduction in the presence of active marks and an increase in the occupancy of H1 at the MCAM promoter. Cell migration and invasion were rescued in H3F3A-depleted cells through MCAM overexpression. Moreover, we identified G9a, a lysine methyltransferase encoded by EHMT2, as an upstream regulator of H3F3A. Therefore, this study identifies a novel H3.3 dependent axis involved in ARMS metastasis. These findings establish the potential of MCAM as a therapeutic target for high-risk ARMS patients. © 2022 The Pathological Society of Great Britain and Ireland.

Intraoperative adverse events among surgeons in Singapore: a multicentre cross-sectional study on impact and support.

BACKGROUND: It is known that many surgeons encounter intraoperative adverse events which can result in Second Victim Syndrome (SVS), with significant detriment to their emotional and physical health. There is, however, a paucity of Asian studies in this space. The present study thus aimed to explore the degree to which the experience of an adverse event is common among surgeons in Singapore, as well as its impact, and factors affecting their responses and perceived support systems. METHODS: A self-administered survey was sent to surgeons at four large tertiary hospitals. The 42-item questionnaire used a systematic closed and open approach, to assess: Personal experience with intraoperative adverse events, emotional, psychological and physical impact of these events and perceived support systems. RESULTS: The response rate was 57.5% (n = 196). Most respondents were male (54.8%), between 35 and 44 years old, and holding the senior consultant position. In the past 12 months alone, 68.9% recalled an adverse event. The emotional impact was significant, including sadness (63.1%), guilt (53.1%) and anxiety (45.4%). Speaking to colleagues was the most helpful support source (66.7%) and almost all surgeons did not receive counselling (93.3%), with the majority deeming it unnecessary (72.2%). Notably, 68.1% of the surgeons had positive takeaways, gaining new insight and improving vigilance towards errors. Both gender and surgeon experience did not affect the likelihood of errors and emotional impact, but more experienced surgeons were less likely to have positive takeaways (p = 0.035). Individuals may become advocates for patient safety, while simultaneously championing the cause of psychological support for others. CONCLUSIONS: Intraoperative adverse events are prevalent and its emotional impact is significant, regardless of the surgeon's experience or gender. While colleagues and peer discussions are a pillar of support, healthcare institutions should do more to address the impact and ensuing consequences.

Nephron sparing surgery and surgical management of intravascular extension of Wilms tumor.

Although general treatment approaches for Wilms tumor differ between Children's Oncology Group and Société Internationale d'Oncologie Pédiatrique-Renal Tumors Study Group protocols, complex tumors that may be candidates for nephron sparing surgery (NSS) and those with intravascular tumor extension represent a management challenge. In both of these scenarios, anatomic considerations are important in guiding management, making these areas of significant similarities in management between the international groups. This paper aims to explore the current approaches to NSS and intravascular tumor extension by both international groups, with attention to the evidence supporting these approaches and current knowledge gaps.

KeyLoop retractor for global gasless laparoscopy: evaluation of safety and feasibility in a porcine model.

BACKGROUND: Many surgeons in low- and middle-income countries have described performing surgery using gasless (lift) laparoscopy due to inaccessibility of carbon dioxide and reliable electricity, but the safety and feasibility of the technique has not been well documented. We describe preclinical testing of the in vivo safety and utility of KeyLoop, a laparoscopic retractor system to enable gasless laparoscopy. METHODS: Experienced laparoscopic surgeons completed a series of four laparoscopic tasks in a porcine model: laparoscopic exposure, small bowel resection, intracorporeal suturing with knot tying, and cholecystectomy. For each participating surgeon, the four tasks were completed in a practice animal using KeyLoop. Surgeons then completed these tasks using standard-of-care (SOC) gas laparoscopy and KeyLoop in block randomized order to minimize learning curve effect. Vital signs, task completion time, blood loss and surgical complications were compared between SOC and KeyLoop using paired nonparametric tests. Surgeons completed a survey on use of KeyLoop compared to gas laparoscopy. Abdominal wall tissue was evaluated for injury by a blinded pathologist. RESULTS: Five surgeons performed 60 tasks in 15 pigs. There were no significant differences in times to complete the tasks between KeyLoop and SOC. For all tasks, there was a learning curve with task completion times related to learning the porcine model. There were no significant differences in blood loss, vital signs or surgical complications between KeyLoop and SOC. Eleven surgeons from the United States and Singapore felt that KeyLoop could be used to safely perform several common surgical procedures. No abdominal wall tissue injury was observed for either KeyLoop or SOC. CONCLUSIONS: Procedure times, blood loss, abdominal wall tissue injury and surgical complications were similar between KeyLoop and SOC gas laparoscopy for basic surgical procedures. This data supports KeyLoop as a useful tool to increase access to laparoscopy in low- and middle-income countries.

The therapeutic potential of RNA Polymerase I transcription inhibitor, CX-5461, in uterine leiomyosarcoma.

BACKGROUND: Uterine leiomyosarcoma is a rare aggressive smooth muscle cancer with poor survival rates. RNA Polymerase I (Pol I) activity is elevated in many cancers supporting tumour growth and prior studies in uterine leiomyosarcoma revealed enlarged nucleoli and upregulated Pol I activity-related genes. This study aimed to investigate the anti-tumour potential of CX-5461, a Pol I transcription inhibitor currently being evaluated in clinical trials for several cancers, against the human uterine leiomyosarcoma cell line, SK-UT-1. METHODS: SK-UT-1 was characterised using genome profiling and western blotting. The anti-tumour effects of CX-5461 were investigated using cell proliferation assays, expression analysis using qRT-PCR, and BrdU/PI based cell cycle analysis. RESULTS: Genetic analysis of SK-UT-1 revealed mutations in TP53, RB1, PTEN, APC and TSC1 & 2, all potentially associated with increased Pol I activity. Protein expression analysis showed dysregulated p53, RB1 and c-Myc. CX-5461 treatment resulted in an anti-proliferation response, G2 phase cell-cycle arrest and on-target activity demonstrated by reduced ribosomal DNA transcription. CONCLUSIONS: SK-UT-1 was confirmed as a representative model of uterine leiomyosarcoma and CX-5461 has significant potential as a novel adjuvant for this rare cancer.

Mutations of 1p genes do not consistently abrogate tumor suppressor functions in 1p-intact neuroblastoma.

BACKGROUND: Deletion of 1p is associated with poor prognosis in neuroblastoma, however selected 1p-intact patients still experience poor outcomes. Since mutations of 1p genes may mimic the deleterious effects of chromosomal loss, we studied the incidence, spectrum and effects of mutational variants in 1p-intact neuroblastoma. METHODS: We characterized the 1p status of 325 neuroblastoma patients, and correlated the mutational status of 1p tumor suppressors and neuroblastoma candidate genes with survival outcomes among 100 1p-intact cases, then performed functional validation of selected novel variants of 1p36 genes identified from our patient cohort. RESULTS: Among patients with adverse disease characteristics, those who additionally had 1p deletion had significantly worse overall survival. Among 100 tumor-normal pairs sequenced, somatic mutations of 1p tumor suppressors KIF1Bß and CHD5 were most frequent (2%) after ALK and ATRX (8%), and BARD1 (3%). Mutations of neuroblastoma candidate genes were associated with other synchronous mutations and concurrent 11q deletion (P = 0.045). In total, 24 of 38 variants identified were novel and predicted to be deleterious or pathogenic. Functional validation identified novel KIF1Bß I1355M variant as a gain-of-function mutation with increased expression and tumor suppressive activity, correlating with indolent clinical behavior; another novel variant CHD5 E43Q was a loss-of-function mutation with decreased expression and increased long-term cell viability, corresponding with aggressive disease characteristics. CONCLUSIONS: Our study showed that chromosome 1 gene mutations occurred frequently in 1p-intact neuroblastoma, but may not consistently abrogate the function of bonafide 1p tumor suppressors. These findings may augment the evolving model of compounding contributions of 1p gene aberrations toward tumor suppressor inactivation in neuroblastoma.

Impact of treatment refusal and abandonment on survival outcomes in pediatric osteosarcoma in Southeast Asia: A multicenter study.

BACKGROUND: Treatment refusal and abandonment (TxRA) are major barriers to improving outcomes among children with sarcomas of the extremities as curative treatment options bearing on amputation or disfiguring surgery, particularly in countries with limited resources. A multi-institutional retrospective study was conducted to determine the predictive factors for TxRA among patients with osteosarcoma associated with survival outcomes across Southeast Asia (SEA). METHODS: Pediatric patients with osteosarcoma treated between January 1998 and December 2017 in four SEA pediatric oncology centers from three countries were studied. Nelson-Aalen estimates, Kaplan-Meier method, and Cox's proportion hazard model were applied to address the cumulative incidence, survival outcomes, and to identify prognostic factors associated with TxRA. RESULTS: From a total of 208 patients with osteosarcoma enrolled; 18 (8.7%) patients refused and 41 (19.7%) patients abandoned treatment. Income classification of countries, age at diagnosis, tumor size, disease extent, chemotherapy protocols, and types of surgery were associated with TxRA. Tumor size more than 15 cm was an independent risk factor associated with TxRA. The 5-year overall and relapse-free survivals were 49.4% and 50.4%, respectively. However, these rates declined further to 37.9% and 35.8%, respectively, when TxRA were considered as events. Tumor size larger than 15 cm and metastatic disease were independent risk factors associated with TxRA-sensitive outcomes. CONCLUSION: The prevalence of TxRA was high in SEA, particularly in lower middle-income countries. Factors associated with TxRA related to tumor burden. Treatment outcomes could be substantially improved by lowering the refusal and abandonment rates.

Conservative antibiotic treatment of pediatric acute uncomplicated appendicitis during the COVID-19 pandemic: a prospective comparative cohort study.

BACKGROUND: Our study aimed to compare the clinical outcomes and cost-efficiency of antibiotic management versus laparoscopic appendectomy for acute uncomplicated appendicitis (AUA) in children during the COVID-19 pandemic when resources were limited and transmission risks uncertain. METHOD: In this prospective comparative cohort study, we analyzed the data of 139 children diagnosed with AUA meeting the following inclusion criteria: 5-18 years of age, symptoms duration of ≤ 48 h, appendix diameter ≤ 11 mm and no appendicolith. Treatment outcomes between non-operative management group (78/139) and upfront laparoscopic appendectomy group (61/139) were compared. Antibiotic regimes were intravenous ceftriaxone/metronidazole or amoxicillin/clavulanic acid for 48 h, followed by oral antibiotics to complete total 10-days course. RESULTS: 8/78 (10.3%) children had early failure (within 48 h) requiring appendectomy. 17/70 (24.3%) patients experienced late recurrence within mean follow-up time of 16.2 ± 4.7 months. There were no statistical differences in peri-operative complications, negative appendicectomy rate, and incidence of perforation and hospitalization duration between antibiotic and surgical treatment groups. Cost per patient in upfront surgical group was significantly higher ($6208.5 ± 5284.0) than antibiotic group ($3588.6 ± 3829.8; p = 0.001). CONCLUSION: Despite 24.3% risk of recurrence of appendicitis in 16.2 ± 4.7 months, antibiotic therapy for AUA appears to be a safe and cost-effective alternative to upfront appendectomy.

Laparoscopic experience and attitudes toward a low-cost laparoscopic system among surgeons in East, Central, and Southern Africa: a survey study.

BACKGROUND: Laparoscopic surgery has become standard of care in high-income countries but is rarely accessible in low- and middle-income countries (LMICs). This study assessed experience with laparoscopy and attitudes toward a low-cost laparoscopic system among surgeons in sub-Saharan Africa. METHODS: A survey assessing current laparoscopic practice and feedback on a low-cost laparoscopic system was administered to attendees of the College of Surgeons of East, Central, and Southern Africa (COSECSA) Scientific Conference between December 4 and December 6, 2019 in Kampala, Uganda. RESULTS: Fifty-six surgeons from 14 countries participated. A majority were male (n = 46, 82%) general surgeons (n = 37, 66%) from tertiary/teaching hospitals (n = 36, 64%). For those with training in laparoscopy (n = 33, 59%), 22 (67%) reported less than 1 year of training and over half (n = 17, 52%) reported 1 month or less. Overall, a minority (n = 21, 38%) used laparoscopy in current practice, with 57% (n = 12) of those performing laparoscopy less than once per week. The most common laparoscopic surgeries performed were cholecystectomy (n = 15), diagnostic laparoscopy (n = 14), and appendectomy (n = 12). Few surgeons were performing more complex cases (n = 5). Barriers to laparoscopy included poor access to training equipment (n = 34, 61%), mentors (n = 33, 59%), laparoscopic equipment (n = 31, 55%), equipment maintenance (n = 25, 45%), access to consumable supplies (n = 21, 38%), and cost (n = 31, 55%). Fifty-two participants (93%) were interested in increasing their use of laparoscopy; the majority felt that a low-cost laparoscope (n = 52, 93%) and lift retractor for gasless laparoscopy (n = 46, 82%) would serve an unmet need in their practice. CONCLUSIONS: While the use of laparoscopy is currently limited in COSECSA countries, there is a significant interest among surgeons to increase implementation. A low-cost, durable laparoscopic system was viewed as a potential solution to the current barriers and could improve implementation in LMICs.

Larotrectinib followed by selitrectinib in a novel DCTN1-NTRK1 fusion undifferentiated pleomorphic sarcoma.

INTRODUCTION: Neurotrophic receptor tyrosine kinase fusions cause overexpression or activation of kinase and are believed to confer oncogenic potential in some non-rhabdomyosarcoma soft tissue sarcomas. TRK inhibitors have recently been shown to induce responses in these tumours though current experience with these agents is still limited. CASE REPORT: We report a case of an adolescent with treatment-refractory non-rhabdomyosarcoma soft tissue sarcomas, carrying a novel DCTN1-NTRK1 gene fusion whose progressive disease was treated with multi-kinase and TRK inhibitors.Management and outcome: Our patient was started on pan-TRK inhibitor larotrectinib, as his disease progressed after chemotherapy, radiation therapy and surgery, based on next-generation sequencing test showing DCTN1-NTRK1 gene fusion. He responded quickly to larotrectinib with the improvement of symptoms and reduction of masses. However, this response was short-lived due to the development of acquired solvent front resistance mutation. This patient did not respond to next-generation TRK inhibitor selitrectinib and eventually succumbed to his disease. DISCUSSION: The initial rapid and drastic response of our patient to larotrectinib was not sustained due to the development of acquired resistance. This case emphasizes the need for upfront and periodic next-generation sequencing testing to guide treatment of patients with refractory non-rhabdomyosarcoma soft tissue sarcomas.

Gastrointestinal and oncologic outcomes of pediatric gastrointestinal lymphoma following upfront resection or biopsy of bowel masses.

PURPOSE: Complete upfront resection of pediatric gastrointestinal lymphomas is recommended over biopsy whenever feasible, but either approach may have adverse sequelae. We sought to compare gastrointestinal and oncological outcomes of pediatric gastrointestinal lymphomas who underwent attempted upfront resection or biopsy of the presenting bowel mass. METHODS: We retrospectively reviewed charts of children with gastrointestinal lymphomas treated on LMB89 and LMB96 protocols from 2000 to 2019 who underwent upfront gastrointestinal surgery, and compared resection and biopsy groups. RESULTS: Of 33 children with abdominal lymphomas, 20 had upfront gastrointestinal surgery-10 each had resection or biopsy. Patients with attempted upfront resections had fewer postoperative gastrointestinal complications compared to biopsies (10% vs. 60%, p = 0.057), but longer time to chemotherapy initiation (median 11.5 vs. 4.5 days, p < 0.001). Three resection patients were surgically down-staged. Second surgeries were required in 30% and 40% of resected and biopsied patients, respectively, at median 4.6 months. Survival was similar in both groups, but better in patients on LMB96 protocol and stage II/III disease. CONCLUSIONS: Children with upfront attempted resection had low rates of surgical down-staging, greater delay in chemotherapy initiation, but fewer gastrointestinal complications and subsequent surgeries than biopsies. Survival was similar regardless of upfront surgery, likely reflecting beneficial effects of newer protocols.

Neuroblastoma patient-derived cultures are enriched for a mesenchymal gene signature and reflect individual drug response.

Ex vivo evaluation of personalized models can facilitate individualized treatment selection for patients, and advance the discovery of novel therapeutic options. However, for embryonal malignancies, representative primary cultures have been difficult to establish. We developed patient-derived cell cultures (PDCs) from chemo-naïve and post-treatment neuroblastoma tumors in a consistent and efficient manner, and characterized their in vitro growth dynamics, histomorphology, gene expression, and functional chemo-response. From 34 neuroblastoma tumors, 22 engrafted in vitro to generate 31 individual PDC lines, with higher engraftment seen with metastatic tumors. PDCs displayed characteristic immunohistochemical staining patterns of PHOX2B, TH, and GD2 synthase. Concordance of MYCN amplification, 1p and 11q deletion between PDCs and patient tumors was 83.3%, 72.7%, and 80.0% respectively. PDCs displayed a predominantly mesenchymal-type gene expression signature and showed upregulation of pro-angiogenic factors that were similarly enriched in culture medium and paired patient serum samples. When tested with standard-of-care cytotoxics at human Cmax -equivalent concentrations, MYCN-amplified and non-MYCN-amplified PDCs showed a differential response to cyclophosphamide and topotecan, which mirrored the corresponding patients' responses, and correlated with gene signatures of chemosensitivity. In this translational proof-of-concept study, early-phase neuroblastoma PDCs enriched for the mesenchymal cell subpopulation recapitulated the individual molecular and phenotypic profile of patient tumors, and highlighted their potential as a platform for individualized ex vivo drug-response testing.

Congenital mesoblastic nephroma is characterised by kinase mutations including EGFR internal tandem duplications, the ETV6-NTRK3 fusion, and the rare KLHL7-BRAF fusion.

AIMS: Congenital mesoblastic nephroma (CMN) is histologically classified into classic, cellular and mixed subtypes. The aims of this study were to characterise the clinical, pathological and molecular features of a series of CMNs, and to determine the utility of pan-Trk and epidermal growth factor receptor (EGFR) immunohistochemistry as surrogate markers for NTRK gene fusions and EGFR internal tandem duplications (ITDs). METHODS AND RESULTS: Twenty-two archival CMN cases (12 classic, five cellular, and five mixed) were tested for the ETV6-NTRK3 fusion and EGFR ITD transcripts by the use of reverse transcriptase polymerase chain reaction (PCR), and next-generation sequencing-based anchored multiplex PCR. All 12 classic CMNs had EGFR ITD. Of the five cellular CMNs, four had the ETV6-NTRK3 fusion and one had the KLHL7-BRAF fusion. Of the five mixed CMNs, four had EGFR ITD, and one had the ETV6-NTRK3 fusion. Pan-Trk immunoreactivity was 100% sensitive and 94.1% specific for the presence of NTRK rearrangement. However, EGFR staining was only 62.5% sensitive and 33.3% specific for EGFR ITD. CONCLUSIONS: EGFR ITD is a consistent genetic event in classic CMN. A majority of cellular CMNs have the ETV6-NTRK3 fusion. Rare cellular CMNs may harbour non-canonical mutations such as the KLHL7-BRAF fusion, which was found in one case. Mixed CMNs may have either EGFR ITD or the ETV6-NTRK3 fusion. Pan-Trk immunohistochemistry is a sensitive, albeit not perfectly specific, marker for NTRK rearrangement. EGFR immunohistochemistry is not helpful as a marker of EGFR ITD.

Clinical, pathological and loss of heterozygosity differences in Wilms tumors between Asian and non-Asian children.

Wilms tumor demonstrates significant interethnic epidemiological, histological and outcome differences, and is rare and poorly studied among Asians. We compared the clinicopathological, and loss of heterozygosity (LOH) profile and survival outcomes of Asian and non-Asian patients with Wilms tumor. Clinical charts and histological slides from patients with malignant renal tumors over a period of 20 years were retrospectively reviewed. We adapted a genotyping assay to determine 1p36 and 16q21-22 LOH in formalin-fixed paraffin-embedded (FFPE) specimens, and compared these characteristics between Asian and non-Asian patients. Fifty-three (79.1%) Asian and 14 (20.9%) non-Asian patients had Wilms tumors. Compared to non-Asians, Asians were younger (mean 4.6 and 4.0 years, respectively), had more equal gender distribution (female: male = 1.8 and 1.0, respectively), fewer tumors with unfavorable histology (25.0% and 4.1%, respectively, p = 0.05), and less advanced disease at presentation, yet similar nodal metastases rates (16.7% and 18.4%, respectively). No Asian patients had bilateral tumors. Our adapted genotyping assay accurately determined LOH in FFPE specimens <10 years post-fixation. Among 30 Asian patients, 1p and 16q LOH were each detected in 5 (16.7%) patients, respectively-similar to rates reported in other ethnicities. Yet after similar treatment with National Wilms Tumor Study regimens, 15-year event-free and overall survival for Asian patients was 95.7% and 96.3% respectively. In summary, despite similar nodal metastasis and LOH rates, Asian patients had fewer unfavorable histology tumors, lower-stage disease, and better survival outcomes. The bases for these differences and implications on treatment strategy for these patients warrant further study.

Primary Adrenal Angiomatoid Fibrous Histiocytoma With Novel EWSR1-ATF1 Gene Fusion Exon-Exon Breakpoint.

We describe the clinical, pathological, and molecular features of a primary adrenal angiomatoid fibrous histiocytoma (AFH) in an 11-year-old girl presenting with pyrexia of unknown origin. We performed next-generation sequencing-based anchored multiplex polymerase chain reaction (Archer® FusionPlex® sarcoma assay), which revealed an EWSR1-ATF1 gene fusion with novel breakpoints in exon 11 of EWSR1 and exon 3 of ATF1. The pyrexia resolved fully after surgical resection, and the patient was disease-free on follow-up at 1 year and 6 months. This case exemplifies the value of molecular testing of pediatric neoplasms presenting at unusual sites for diagnosis and identification of novel gene fusion breakpoints.

Evaluation of a Novel Bony Landmark-Based Method for Teaching Percutaneous Insertion of Subclavian Venous Catheters in Pediatric Patients.

BACKGROUND: Surgical trainees performing subclavian vein (SCV) cannulation often incorrectly perceive needle trajectory and anatomical relations. As surface landmark-based methods derived from adult surgical practice may be less effective in younger patients, we developed and evaluated a novel bony landmark-based method for teaching SCV cannulation for central venous access device (CVAD) placement in children. METHODS: Over 2 sequential 3-year periods, pediatric surgical trainees were taught infraclavicular SCV cannulation via surface- and bony-landmark approaches, respectively. We prospectively recorded patient, surgeon and operative details on all Hickman line and port-a-cath insertions placed by trainees as the first surgeon via percutaneous infraclavicular SCV puncture and compared procedural outcomes and complications across both periods. RESULTS: Of 271 cases included in the study, trainees performed 52 (50.5%) and 92 (54.8%) procedures in the first and second periods, respectively. Patients in both periods did not differ by gender, disease, CVAD device, or prior CVAD, chemotherapy or infection status. In the second (bony landmark) period, although patients were younger (6.0 vs. 8.7 years, P = 0.003) mean procedural duration was shorter (42.5 vs. 58.3 min, P < 0.001). Also, cannulation attempts and complication rates did not differ significantly between study periods (P = 0.257 and 1.0, respectively). CONCLUSIONS: With the bony landmark approach, trainees could perform the procedures faster despite operating on younger patients, without impacting complication rates and cannulation attempts. Bony landmarks may better approximate SCV position across a range of ages, thus improving the consistency of SCV cannulation in CVAD placements in children.

Clear cell sarcomas of the kidney are characterised by BCOR gene abnormalities, including exon 15 internal tandem duplications and BCOR-CCNB3 gene fusion.

AIMS: Clear cell sarcoma of the kidney (CCSK) is a rare paediatric renal malignant tumour. The majority of CCSKs have internal tandem duplications (ITDs) of the BCOR gene, whereas a minority have the YWHAE-NUTM2 gene fusion. A third 'double-negative' (DN) category comprises CCSKs with neither BCOR ITDs nor YWHAE-NUTM2 fusion. The aim of this study was to characterise 11 histologically diagnosed CCSKs immunohistochemically (with CCND1, BCOR and CCNB3 stains) and genetically. METHODS AND RESULTS: By next-generation sequencing, 10 cases (90.9%) had BCOR exon 15 ITDs, with positive BCOR immunoreactivity being found in four (36%) or eight (72%) cases, depending on the antibody clone. By reverse transcription polymerase chain reaction, none had the YWHAE-NUTM2 fusion. The DN case had a BCOR-CCNB3 fusion and strong nuclear CCNB3 and BCOR immunoreactivity. Quantitative polymerase chain reaction showed markedly elevated BCOR expression in this case, whereas BCOR ITD cases had lower levels of elevated BCOR expression. CONCLUSIONS: The majority of the CCSKs in our cohort had BCOR ITDs, and none had the YWHAE-NUTM2 fusion. We verified the strong, diffuse cyclin D1 (CCND1) immunoreactivity in CCSKs described in recent reports. BCOR immunoreactivity was not consistently positive in all CCSKs with BCOR ITDs, and therefore cannot be used as a diagnostic immunohistochemical stain to identify BCOR ITD cases. The DN case was a BCOR-CCNB3 fusion sarcoma. BCOR-CCNB3 sarcoma is typically a primary bone sarcoma affecting male adolescents, and this is the first report of it presenting in a kidney of a young child as a CCSK. The full spectrum of DN CCSKs awaits more comprehensive characterisation.

Safety and diagnostic accuracy of tumor biopsies in children with cancer.

BACKGROUND: Tumor biopsies are central to the diagnosis and management of cancer and are critical to efforts in personalized medicine and targeted therapeutics. In the current study, the authors sought to evaluate the safety and accuracy of biopsies in children with cancer. METHODS: All biopsies performed in children at the study institution with a suspected or established diagnosis of cancer from 2003 through 2012 were reviewed retrospectively. Patient characteristics and disease-related and procedure-related factors were correlated with procedure-related complications and diagnostic accuracy using logistic regression analysis. RESULTS: A total of 1073 biopsies were performed in 808 patients. Of 1025 biopsies with adequate follow-up, 79 (7.7%) were associated with an adverse event, 35 (3.4%) of which were minor (grade 1-2) and 32 (3.1%) of which were major (grade 3-4) (grading was performed according to the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0]). The most common major adverse events were blood transfusion (>10 mL/kg; 24 cases) and infection requiring intravenous antibiotics (6 cases). Eleven deaths (1.4%) occurred within 30 days after the procedure, but the procedure may have contributed to the outcome in only 2 cases. A total of 926 biopsies (90.3%) provided definitive histologic diagnoses. Using multivariable analysis, biopsy site, preprocedure hematocrit level, and body mass index were found to be associated with the risk of postprocedural complications (P<.0001, P<.0001, and P =.0029, respectively). Excisional biopsy and biopsy site were found to be independently associated with obtaining a diagnostic result (P =.0002 and P =.0008, respectively). CONCLUSIONS: Tumor biopsies in children with cancer are associated with a low incidence of complications and a high rate of diagnostic accuracy. The predictive factors identified for adverse outcomes may aid in risk assessment and preprocedural counseling.