Pediatric renal tumor epidemiology: Global perspectives, progress, and challenges.

Pediatric renal tumors account for 3%-11% of childhood cancers, the most common of which is Wilms tumor or nephroblastoma. Epidemiology plays a key role in cancer prevention and control by describing the distribution of cancer and discovering risk factors for cancer. Large pediatric research consortium trials have led to a clearer understanding of pediatric renal tumors, identification of risk factors, and development of more risk-adapted therapies. These therapies have improved event-free and overall survival for children. However, several challenges remain and not all children have benefited from the improved outcomes. In this article, we review the global epidemiology of pediatric renal tumors, including key consortium and global studies. We identify current knowledge gaps and challenges facing both high and low middle-incomes countries.

Pediatric renal tumor epidemiology: Global perspectives, progress, and challenges.

Pediatric renal tumors account for 3%-11% of childhood cancers, the most common of which is Wilms tumor or nephroblastoma. Epidemiology plays a key role in cancer prevention and control by describing the distribution of cancer and discovering risk factors for cancer. Large pediatric research consortium trials have led to a clearer understanding of pediatric renal tumors, identification of risk factors, and development of more risk-adapted therapies. These therapies have improved event-free and overall survival for children. However, several challenges remain and not all children have benefited from the improved outcomes. In this article, we review the global epidemiology of pediatric renal tumors, including key consortium and global studies. We identify current knowledge gaps and challenges facing both high and low middle-incomes countries.

Implementation of a formalized evaluation and planning tool to improve pediatric oncology outcomes in Kenya.

BACKGROUND: Survival from pediatric cancers in low middle-income countries is often very low compared to that of high-income countries due to multifactorial etiologies, including late presentation, delayed diagnosis, difficulty with accessing healthcare, drug unavailability, and treatment abandonment. The St. Jude Pediatric Oncology Facility Integrated Local Evaluation Tool (PrOFILE) was developed to map and evaluate childhood cancer healthcare delivery in individual institutions and entire countries, identifying the strengths and weaknesses, as well as opportunities for advancement of care. PROCEDURE: Using the PrOFILE self-assessment tool, selected Kenyan pediatric oncology facilities entered data into 12 modules: national context, facility and local context, finances and resources, personnel, service capacity, service integration, diagnostics, chemotherapy, supportive care, surgery, radiation therapy, and patients and outcomes. These modules are grouped into five specific components, including Context, Workforce, Diagnostics, Therapy, and Patients and Outcomes. The St. Jude PrOFILE team analyzed the data and organized the first hybrid workshop, containing both in-person and virtual components. RESULTS: Multidisciplinary stakeholders prioritized recommendations for improving care and developed smart objectives to accomplish identified goals over the following 2 years. Strengths and weaknesses of conducting a hybrid global workshop were identified. CONCLUSIONS: We demonstrated successful use of the PrOFILE tool to conduct a hybrid workshop and identify strategies to improve pediatric oncology care in Kenya. The voluntarily structured work groups will methodically aim to achieve outcome-oriented goals moving forward.

"Money was the problem": Caregivers' self-reported reasons for abandoning their children's cancer treatment in southwest Uganda.

INTRODUCTION: Treatment abandonment contributes significantly to poor survival of children with cancer in low- and middle-income countries (LMIC). In order to inform an approach to this problem, we investigated why caregivers withdraw their children from treatment. METHODS: In a qualitative study, carried out in October and November 2020, in-depth interviews were conducted with caregivers of children who had abandoned cancer treatment at the Pediatric Cancer Unit of Mbarara Regional Referral Hospital in south-western Uganda. Recorded in-depth interviews were transcribed and analyzed to identify themes of caregivers' self-reported reasons for treatment abandonment. The study was approved by the Review and Ethics Committee of Mbarara University of Science and Technology. RESULTS: Seventy-seven out of 343 (22.4%) children diagnosed with cancer abandoned treatment during the study period; 20 contactable and consenting caregivers participated in the study. The median age of the caregivers was 37 years and most (65%) were mothers. At the time of this study, eight (40%) children were alive and five (62.5%) were males; with a median age of 6.5 years. Financial difficulty, other obligations, the child falsely appearing cured, preference for alternative treatments, belief that cancer was incurable, fear that the child's death was imminent and chemotherapy side effects were the caregivers' reasons for treatment abandonment. CONCLUSIONS AND RECOMMENDATION: Seeking cancer treatment for children in Uganda is an expensive venture and treatment abandonment is mainly caused by caregivers' difficult socio-economic circumstances. This problem needs to be approached with empathy and support rather than blame.

Genetic and chromosomal alterations in Kenyan Wilms Tumor.

Wilms tumor (WT) is the most common childhood kidney cancer worldwide and poses a cancer health disparity to black children of sub-Saharan African ancestry. Although overall survival from WT at 5 years exceeds 90% in developed countries, this pediatric cancer is alarmingly lethal in sub-Saharan Africa and specifically in Kenya (36% survival at 2 years). Although multiple barriers to adequate WT therapy contribute to this dismal outcome, we hypothesized that a uniquely aggressive and treatment-resistant biology compromises survival further. To explore the biologic composition of Kenyan WT (KWT), we completed a next generation sequencing analysis targeting 10 WT-associated genes and evaluated whole-genome copy number variation. The study cohort was comprised of 44 KWT patients and their specimens. Fourteen children are confirmed dead at 2 years and 11 remain lost to follow-up despite multiple tracing attempts. TP53 was mutated most commonly in 11 KWT specimens (25%), CTNNB1 in 10 (23%), MYCN in 8 (18%), AMER1 in 5 (11%), WT1 and TOP2A in 4 (9%), and IGF2 in 3 (7%). Loss of heterozygosity (LOH) at 17p, which covers TP53, was detected in 18% of specimens examined. Copy number gain at 1q, a poor prognostic indicator of WT biology in developed countries, was detected in 32% of KWT analyzed, and 89% of these children are deceased. Similarly, LOH at 11q was detected in 32% of KWT, and 80% of these patients are deceased. From this genomic analysis, KWT biology appears uniquely aggressive and treatment-resistant.

Risk factors for abandonment of Wilms tumor therapy in Kenya.

BACKGROUND: Survival from Wilms tumor (WT) in sub-Saharan Africa remains dismal as a result of on-therapy mortality and treatment abandonment. Review of patients diagnosed from 2008 to 2011 in our Kenyan Wilms Tumor Registry showed a loss to follow up (LTFU) rate approaching 50%. The purpose of this study was to trace those LTFU, estimate the survival rate, and identify risk factors for treatment abandonment. PROCEDURE: We administered a comprehensive survey to parents of patients with WT at the two largest referral hospitals in Kenya to identify barriers to care. We also telephoned families who had abandoned care to determine vital status and identify risk factors for treatment abandonment. RESULTS: Of 136 registered patients, 77 were confirmed dead (56.7%), 38 remained alive (27.9%), and the vital status of 21 patients remains unknown (15.4%). After contacting 33 of the patients who either abandoned curative treatment (n = 34) or did not attend off-therapy visits (n = 20), the best estimate of 2-year overall survival of patients with WT in Kenya approaches 36%. Sixty-three percent of parents misunderstood treatment plans and 55% encountered financial barriers. When asked how to increase comfort with the child's treatment, 27% of parents volunteered improving inefficient services and 26% volunteered reducing drug-unavailability. CONCLUSIONS: Treatment abandonment remains a significant problem contributing to increased mortality from WT in developing countries. This multi-center survey identified the barriers to treatment completion from the parental perspective to be lack of education about WT and treatment, financial constraints, need for quality improvement, and drug-unavailability. Pediatr Blood Cancer 2015;62:252-256. © 2014 Wiley Periodicals, Inc.

Aberrant activation, nuclear localization, and phosphorylation of Yes-associated protein-1 in the embryonic kidney and Wilms tumor.

BACKGROUND: The Yes-associated-protein-1 (YAP1) is a novel, direct regulator of stem cell genes both in development and cancer. FAT4 is an upstream regulator that induces YAP1 cytosolic sequestering by phosphorylation (p-Ser 127) and therefore inhibits YAP1-dependent cellular proliferation. We hypothesized that loss of FAT4 signaling would result in expansion of the nephron progenitor population in kidney development and that YAP1 subcellular localization would be dysregulated in Wilms tumor (WT), an embryonal malignancy that retains gene expression profiles and histologic features reminiscent of the embryonic kidney. METHODS: Fetal kidneys from Fat4(-/-) mice were harvested at e18.5 and markers of nephron progenitors were investigated using immunohistochemical analysis. To examine YAP1 subcellular localization in WT, a primary WT cell line (VUWT30) was analyzed by immunofluorescence. Forty WT specimens evenly distributed between favorable and unfavorable histology (n = 20 each), and treatment failure or success (n = 20 each) was analyzed for total and phosphorylated YAP1 using immunohistochemistry and Western blot. RESULTS: Fat4(-/-) mouse fetal kidneys exhibit nuclear YAP1 with increased proliferation and expansion of nephron progenitor cells. In contrast to kidney development, subcellular localization of YAP1 is dysregulated in WT, with a preponderance of nuclear p-YAP1. By Western blot, median p-YAP1 quantity was 5.2-fold greater in unfavorable histology WT (P = 0.05). CONCLUSIONS: Fetal kidneys in Fat4(-/-) mice exhibit a phenotype reminiscent of nephrogenic rests, a WT precursor lesion. In WT, YAP1 subcellular localization is dysregulated and p-YAP1 accumulation is a novel biomarker of unfavorable histology.

Development and pilot testing of PROACTIVE: A pediatric onco-critical care capacity and quality assessment tool for resource-limited settings.

BACKGROUND: Nearly 90% children with cancer reside in low- and middle-income countries, which face multiple challenges delivering high-quality pediatric onco-critical care (POCC). We recently identified POCC quality and capacity indicators for PROACTIVE (PediatRic Oncology cApaCity assessment Tool for IntensiVe carE), a tool that evaluates strengths and limitations in POCC services. This study describes pilot testing of PROACTIVE, development of center-specific reports, and identification of common POCC challenges. METHODS: The original 119 consensus-derived PROACTIVE indicators were converted into 182 questions divided between 2 electronic surveys for intensivists and oncologists managing critically ill pediatric cancer patients. Alpha-testing was conducted to confirm face-validity with four pediatric intensivists. Eleven centers representing diverse geographic regions, income levels, and POCC services conducted beta-testing to evaluate usability, feasibility, and applicability of PROACTIVE. Centers' responses were scored and indicators with mean scores ≤75% in availability/performance were classified as common POCC challenges. RESULTS: Alpha-testing ensured face-validity and beta-testing demonstrated feasibility and usability of PROACTIVE (October 2020-June 2021). Twenty-two surveys (response rate 99.4%) were used to develop center-specific reports. Adjustments to PROACTIVE were made based on focus group feedback and surveys, resulting in 200 questions. Aggregated data across centers identified common POCC challenges: (1) lack of pediatric intensivists, (2) absence of abstinence and withdrawal symptoms monitoring, (3) shortage of supportive care resources, and (4) limited POCC training for physicians and nurses. CONCLUSIONS: PROACTIVE is a feasible and contextually appropriate tool to help clinicians and organizations identify challenges in POCC services across a wide range of resource-levels. Widespread use of PROACTIVE can help prioritize and develop tailored interventions to strengthen POCC services and outcomes globally.

Pediatric Solid Tumors in Resource-Constrained Settings: A Review of Available Evidence on Management, Outcomes, and Barriers to Care.

International disparities in outcomes from pediatric solid tumors remain striking. Herein, we review the current literature regarding management, outcomes, and barriers to care for pediatric solid tumors in low- and middle-income countries (LMICs). In sub-Saharan Africa, Wilms Tumor represents the most commonly encountered solid tumor of childhood and has been the primary target of recent efforts to improve outcomes in low-resource settings. Aggressive and treatment-resistant tumor biology may play a role in poor outcomes within certain populations, but socioeconomic barriers remain the principal drivers of preventable mortality. Management protocols that include measures to address socioeconomic barriers have demonstrated early success in reducing abandonment of therapy. Further work is required to improve infrastructure and general pediatric care to address disparities.

SPARC overexpression suppresses radiation-induced HSP27 and induces the collapse of mitochondrial Δψ in neuroblastoma cells.

Neuroblastoma is the cause of >15% of cancer-associated mortality in children in the USA. Despite aggressive treatment regimens, the long-term survival rate for these children remains at <40%. The current study demonstrates that secreted protein acidic and rich in cysteine (SPARC) suppresses radiation-induced expression of heat shock protein 27 (HSP27) in vivo and suppresses mitochondrial membrane potential (Δψ) in neuroblastoma cells. In the present study, the overexpression of SPARC in SK-N-BE(2) and NB1691 neuroblastoma cell lines suppresses radiation-induced G2M cell cycle arrest, proliferation, HSP27 expression (in vitro and in vivo) and induces the collapse of the mitochondrial Δψ. Gene ontology analysis demonstrated that the overexpression of SPARC combined with irradiation, induces the expression of dissimilar molecular function genes in SK-N-BE(2) and NB1691 cells, providing evidence of a dissimilar response signaling pathway. These results demonstrate that overexpression of SPARC suppresses radiation-induced HSP27 expression in neuroblastoma cells and the combination of SPARC and radiation induces the expression of protein 21, but suppresses neuroblastoma tumor density in in vivo mouse models. SPARC also induces mitochondrial Δψ collapse in SK-N-BE(2) and NB1691 neuroblastoma cells.

Race disparities in peptide profiles of North American and Kenyan Wilms tumor specimens.

BACKGROUND: Wilms tumor (WT) is the most common childhood kidney cancer worldwide and arises in children of black African ancestry with greater frequency and severity than other race groups. A biologic basis for this pediatric cancer disparity has not been previously determined. We hypothesized that unique molecular fingerprints might underlie the variable incidence and distinct disease characteristics of WT observed between race groups. STUDY DESIGN: To evaluate molecular disparities between WTs of different race groups, the Children's Oncology Group provided 80 favorable histology specimens divided evenly between black and white patients and matched for disease characteristics. As a surrogate of black sub-Saharan African patients, we also analyzed 18 Kenyan WT specimens. Tissues were probed for peptide profiles using matrix-assisted laser desorption ionization time of flight imaging mass spectrometry. To control for histologic variability within and between specimens, cellular regions were analyzed separately as triphasic (containing blastema, epithelia, and stroma), blastema only, and stroma only. Data were queried using ClinProTools and statistically analyzed. RESULTS: Peptide profiles, detected in triphasic WT regions, recognized race with good accuracy, which increased for blastema- or stroma-only regions. Peptide profiles from North American WTs differed between black and white race groups but were far more similar in composition than Kenyan specimens. Individual peptides were identified that also associated with WT patient and disease characteristics (eg, treatment failure and stage). Statistically significant peptide fragments were used to sequence proteins, revealing specific cellular signaling pathways and candidate drug targets. CONCLUSIONS: Wilms tumor specimens arising among different race groups show unique molecular fingerprints that could explain disparate incidences and biologic behavior and that could reveal novel therapeutic targets.

CITED1 expression in liver development and hepatoblastoma.

Hepatoblastoma, the most common pediatric liver cancer, consists of epithelial mixed embryonal/fetal (EMEF) and pure fetal histologic subtypes, with the latter exhibiting a more favorable prognosis. Few embryonal histology markers that yield insight into the biologic basis for this prognostic discrepancy exist. CBP/P-300 interacting transactivator 1 (CITED1), a transcriptional co-activator, is expressed in the self-renewing nephron progenitor population of the developing kidney and broadly in its malignant analog, Wilms tumor (WT). In this current study, CITED1 expression is detected in mouse embryonic liver initially on post-coitum day 10.5 (e10.5), begins to taper by e14.5, and is undetectable in e18.5 and adult livers. CITED1 expression is detected in regenerating murine hepatocytes following liver injury by partial hepatectomy and 3,5-diethoxycarbonyl-1,4-dihydrocollidine. Importantly, while CITED1 is undetectable in normal human adult livers, 36 of 41 (87.8%) hepatoblastoma specimens express CITED1, where it is enriched in EMEF specimens compared to specimens of pure fetal histology. CITED1 overexpression in Hep293TT human hepatoblastoma cells induces cellular proliferation and upregulates the Wnt inhibitors Kringle containing transmembrane protein 1 (KREMEN1) and CXXC finger protein 4 (CXXC4). CITED1 mRNA expression correlates with expression of CXXC4 and KREMEN1 in clinical hepatoblastoma specimens. These data show that CITED1 is expressed during a defined time course of liver development and is no longer expressed in the adult liver but is upregulated in regenerating hepatocytes following liver injury. Moreover, as in WT, this embryonic marker is reexpressed in hepatoblastoma and correlates with embryonal histology. These findings identify CITED1 as a novel marker of hepatic progenitor cells that is re-expressed following liver injury and in embryonic liver tumors.