Phase II Clinical Trial for Newly Diagnosed Children and Adolescents with Localized Lymphoblastic Lymphoma (Japanese Leukemia/Lymphoma Study Group Trial LLB-NHL03) : Study Protocol for Nationwide Multicenter Trial.

Pediatric patients with lymphoblastic lymphoma are generally treated using the Berlin-Frankfurt-Munster (BFM) 90 protocol, which is the standard treatment strategy for pediatric acute lymphoblastic leukemia, and have a favorable outcome. However, this intense regimen includes high total doses of anthracycline and alkylating agents, and is known to cause late complications. We therefore planned a clinical trial to examine the efficacy and safety of a modified BFM regimen. We expect that this phase II, nationwide multicenter trial will help to establish an effective and safer standard therapy for stage I/II pediatric lymphoblastic lymphoma.

Secondary bone/soft tissue sarcoma in childhood cancer survivors: a nationwide hospital-based case-series study in Japan.

BACKGROUND: Secondary cancer is the most life-threatening late effect of childhood cancer. We investigated the clinical features of secondary bone/soft tissue sarcoma among childhood cancer survivors (CCSs). METHODS: We conducted a retrospective case-series study of 10 069 CCSs newly diagnosed with cancer between 1980 and 2009 across 15 Japanese hospitals. Twenty-one cases of pathologically diagnosed secondary bone/soft tissue sarcoma were selected, and the respective clinical courses were determined using additional questionnaires. RESULTS: The primary cancers included retinoblastoma (n = 7), acute lymphoblastic leukemia (n = 5), lymphoma (n = 5), osteosarcoma (n = 1), rhabdomyosarcoma (n = 1), brain tumor (n = 1) and Langerhans cell histiocytosis (n = 1). The median age at the primary cancer diagnosis was 2.9 years, and the male-to-female ratio was 16:5. The histological classifications of the secondary sarcoma included osteosarcoma (n = 10), malignant peripheral nerve sheath tumor (n = 4), rhabdomyosarcoma (n = 3), Ewing's sarcoma (n = 3) and primitive neuroectodermal tumor (n = 1). The median latency period to the secondary sarcoma was 10.2 years. Significant risk factors for secondary sarcoma in the multivariate Cox regression model included a history of retinoblastoma as the primary cancer (hazard ratio [HR], 20.9; 95% confidence interval [CI], 5.70-76.5) and autologous stem cell transplantation (SCT) (HR, 2.56; 95% CI, 1.08-6.03). Seventeen CCSs with secondary sarcoma underwent radiation, and nine, hematopoietic SCT. Twelve CCSs with secondary sarcoma achieved disease-free survival, while CCSs with hematological cancer or relapsed primary cancer who developed secondary sarcoma had the worst prognoses. CONCLUSION: The prognoses of CCSs with secondary sarcoma may depend on the primary cancer or prior relapse of primary cancer.

Secondary cancer after a childhood cancer diagnosis: viewpoints considering primary cancer.

BACKGROUNDS: Multidisciplinary therapy has increased the risk of subsequent late effects, but detailed analyses on secondary cancers in childhood cancer survivors (CCSs) are limited in Asian countries. METHODS: This was a retrospective cohort study comprising 10,069 CCSs who were diagnosed between 1980 and 2009 across 15 Japanese hospitals. We conducted secondary analyses to estimate the incidence of secondary cancer according to each primary malignancy and to elucidate the association between primary and secondary cancers. We also explored the risk factors for the development of secondary cancer in each independent primary malignancy. RESULTS: The cumulative incidence of secondary cancer at 20 years varied among primary cancers: hematological malignancy, 3.1% (95% CI 2.2-4.3); retinoblastoma, 6.6% (95% CI 1.5-16.8); pediatric solid tumor, 2.5% (95% CI 1.3-4.2); brain tumors, 5.2% (95% CI 1.7-11.8) bone/soft tissue sarcoma, 5.2% (95% CI 2.3-10.1); and others, 3.3% (95% CI 1.6-6.0) (p = 0.015). The cumulative incidence of secondary cancers is highest in those with osteosarcoma (13.1%) followed by those with hepatoblastoma (8.4%) and retinoblastoma (6.6%). Close association between the primary and secondary cancer diagnoses was found. The risk factors for secondary cancer development depended on the primary cancer, but autologous/allogeneic stem cell transplantation was a relatively common risk factor. CONCLUSION: The cumulative incidence of secondary cancer varied among primary cancers. The primary cancer was closely associated with the secondary cancer but stem cell transplantation was a common risk factor for secondary cancers among CCSs.

Clinical Features and Prognosis According to Immunophenotypic Subtypes Including the Early T-Cell Precursor Subtype of T-Lymphoblastic Lymphoma in the Japanese Pediatric Leukemia/Lymphoma Study Group ALB-NHL03 Study.

We reviewed the immunophenotypic subtypes of pediatric T-cell lymphoblastic lymphoma in the Japanese Pediatric Leukemia/Lymphoma Study Group ALB-NHL03 study. Of the 104 patients, 40 patients each had sufficient data to evaluate the immunophenotypes and early T-cell precursor (ETP) subtype. Pro-T, pre-T, intermediate T, and mature T cells were observed in 1, 9, 21, and 9 cases, respectively. The 3-year event-free survival (EFS) rates of those with pro-T/pre-T, intermediate T, and mature T cells were 80.0±12.6%, 71.4±9.9%, and 88.9±10.5%, respectively (P=0.546). There were 8 and 32 cases of ETP and non-ETP subtypes, with 3-year EFS rates of 75.0±15.3% and 71.9±8.0%, respectively (P=0.828), indicating that the immunophenotypic subtype was not predictive of EFS in this study.

Intensified and prolonged therapy comprising cytarabine, vincristine and prednisolone improves outcome in patients with multisystem Langerhans cell histiocytosis: results of the Japan Langerhans Cell Histiocytosis Study Group-02 Protocol Study.

The JLSG-96 study reported very low mortality rates for children newly diagnosed with multifocal Langerhans cell histiocytosis (LCH). The JLSG-02 study was performed to further improve the prognosis from 2002 to 2009. The present study compared the therapeutic results of these two studies in terms of multisystem disease. All patients were treated with 6 weeks of the Induction A regimen, comprising cytarabine, vincristine and prednisolone, followed by maintenance therapy. Poor responders to Induction A were switched to Induction B. JLSG-02 has been revised from JLSG-96 in the following respects: prednisolone dosage during Induction A increased; duration of maintenance therapy extended from 24 to 48 weeks; cyclosporine introduced to Induction B for progressive disease. One hundred forty-seven children with multisystem LCH were evaluated. Of these, 84 were positive for risk of organ involvement (RO) and 63 were RO-negative. At the 6-week point, 76.2 % of RO+ and 93.7 % of RO- patients responded to Induction A. Five-year event-free survival (EFS) was 46.2 % [95 % confidence (CI), 35.5-56.9] for RO+ and 69.7 % (58.4-81.1) for RO-, which was significantly superior to that in JLSG-96 [26.8 % (13.3-40.4) and 38.9 % (16.4-61.4), respectively]. The intensified induction and prolonged maintenance regimens in JLSG-02 improved EFS in patients with multisystem LCH.

Secondary cancers after a childhood cancer diagnosis: a nationwide hospital-based retrospective cohort study in Japan.

BACKGROUND: The epidemiology of secondary cancers in childhood cancer survivors has been unknown in Asian countries. Our aim is to assess the incidence and risk factors for secondary cancers through a nationwide survey in Japan. METHODS: A retrospective cohort study comprising 10,069 children who were diagnosed with cancer between 1980 and 2009 was conducted in 15 Japanese hospitals. The cumulative incidence rate was calculated using death as the competing risk and compared by the Gray method. The standardized incidence ratio (SIR) was defined as the ratio of the number of observed cancers divided by the number of expected cancers. The risk factors were analyzed using Cox regression analysis. RESULTS: One hundred and twenty-eight patients (1.3 %) developed secondary cancers within a median follow-up of 8.4 years. The cumulative incidence rate was 1.1 % (95 % confidence interval [CI] 0.9-1.4) at 10 years and 2.6 % (95 % CI 2.1-3.3) at 20 years after primary cancer diagnosis. Sensitivity analysis, limited to 5-year survivors (n = 5,387), confirmed these low incidence rates. The SIR of secondary cancers was 12.1 (95 % CI 10.1-14.4). In the Cox analysis, the hazard ratios for secondary cancers were 3.81 (95 % CI 1.53-9.47) for retinoblastoma, 2.78 (95 % CI 1.44-5.38) for bone/soft tissue sarcomas, and 1.81 (95 % CI 1.16-2.83) for allogeneic stem cell transplantation. CONCLUSIONS: The cumulative incidence of secondary cancers in children in Japan was not high; however, the SIR was relatively high. Retinoblastoma or sarcoma in addition to allogeneic stem cell transplantation were significant risk factors for secondary cancers.

Prognostic Impact of Intensified Maintenance Therapy on Children With Advanced Lymphoblastic Lymphoma: A Report From the Japanese Pediatric Leukemia/Lymphoma Study Group ALB-NHL03 Study.

BACKGROUND: Childhood advanced lymphoblastic lymphoma (LBL) has a favorable outcome with an event-free survival (EFS) rate of over 80% in response to treatment strategies for acute lymphoblastic leukemia (ALL). However, no progress has been made in this outcome over the past 10 years. PROCEDURE: We conducted the first nationwide prospective study of childhood advanced LBL to assess the efficacy and safety of ALL-directed therapy with an intensified maintenance phase. We omitted local radiotherapy including prophylactic cranial radiotherapy except for patients with initial central nervous system disease. The total duration of the treatment was 24 months. RESULTS: For the 136 patients analyzed in this study, 5-year overall survival (OS) was 82.9% and 5-year EFS was 77.9%. Thirty events were observed and 14 occurred before the initiation of intensified maintenance phase. Of 14 events, nine were observed as mediastinal enlargement. There was no significant difference in outcome when stratified according to gender or by immunophenotype. The 5-year EFS according to clinical stage in patients with T-cell LBL (T-LBL) was 70.6% for stage III and 88.9% for stage IV (P = 0.037). CONCLUSIONS: Our first nationwide study provided about 80% cure rate with only one case of toxic death in childhood advanced LBL. However, our intensified maintenance therapy could not improve the survival outcome. There was a trend of better EFS in Japanese patients with T-LBL stage IV than T-LBL stage III.

Glycolipid dynamics in generation and differentiation of induced pluripotent stem cells.

Glycosphingolipids (GSLs) are glycoconjugates that function as mediators of cell adhesion and modulators of signal transduction. Some well-defined markers of undifferentiated human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) are glycoconjugates, such as SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81. However, Comprehensive GSL profiles of hiPSCs have not yet been elucidated. The global images of GSLs from the parental cells, hiPSCs, and differentiated cells revealed that there are parental cell-independent specific glycolipids, including Globo H (fucosyl-Gb5Cer) and H type1 antigen (fucosyl-Lc4Cer) that are novel markers for undifferentiated hiPSCs. Interestingly, undifferentiated hiPSCs expressed H type 1 antigen, specific for blood type O, regardless of the cells' genotypes. Thus, in this study, we defined the dynamics of GSL remodeling during reprogramming from parental cell sets to iPSC sets and thence to iPSC-neural cells.

Childhood cancer mortality in Japan, 1980-2013.

BACKGROUND: This study aimed to provide an updated analysis of childhood cancer mortality rates and long-term trends to 2013 to describe the current level of deaths and identify changes in recent decades. METHODS: Data on number of deaths from cancer in children aged under 15 years were derived from Vital Statistics in Japan and the World Health Organization (WHO) mortality database for comparison countries. Trends in mortality were examined by fitting a joinpoint regression model. RESULTS: For all cancers combined, the mortality rate during 2010-2013 was 19.9 per 1,000,000 population for boys and 17.5 for girls in Japan. Mortality from all cancers combined decreased significantly from 1980 to 2003 for boys and from 1980 to 2001 for girls. Afterwards, the rates remained stable for both sexes. Mortality from leukemia declined over the entire study period by 4.6% per year (p<0.05) in boys and 4.3% per year (p<0.05) in girls. For central nervous system (CNS) tumors, a slight increase in mortality was observed for both sexes, with a statistically significant annual percent change (APC) of 0.5% (p<0.05) for boys and 0.6% (p<0.05) for girls. CONCLUSIONS: We provided updated information on recent trends of childhood cancer death. The establishment of a nationwide, childhood cancer registry is required in Japan. Moreover, trends in cancer mortality should be monitored continuously.

Prognostic impact of cytogenetic abnormalities in children and adolescents with mature B-cell non-Hodgkin lymphoma: A report from the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG).

Little information is available on cytogenetic abnormalities and their prognostic importance in childhood mature B-cell non-Hodgkin lymphoma (B-NHL). We performed a review of 79 abnormal karyotypes in childhood B-NHL treated by a uniform protocol. Del(17p) was independently associated with significantly inferior event-free survival in Burkitt or Burkitt-like lymphoma. The adverse prognosis of MYC/8q24 rearrangement, +7q or del(13q), was not observed, which had been suggested as risk factors in FAB/LMB96. Our results imply the possible existence of a biological difference among ethnicities and should be useful to narrow down the gene causing poor prognosis in childhood B-NHL.

Statistical analysis of relation between plasma methotrexate concentration and toxicity in high-dose methotrexate therapy of childhood nonHodgkin lymphoma.

BACKGROUND: Plasma monitoring of Methotrexate (MTX) levels is a standard approach to predict MTX-related toxicities in a high-dose (HD) MTX monotherapy for childhood acute lymphoblastic leukemia. However, it is uncertain whether plasma MTX levels can predict MTX-related toxicity in the HDMTX plus additional chemotherapy for childhood B-cell nonHodgkin lymphoma (B-NHL). PROCEDURES: To statistically analyze the relationship between MTX pharmacokinetic parameters and MTX-related toxicities, we collected data from patients with delayed MTX elimination (≥1 µM at 48 hr and/or ≥0.5 µM at 72 hr) in the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) BNHL 03 study. Blood MTX levels were measured at 24, 48, and 72 hr after 3 or 5 g/m2 HD-MTX administration for 24 hr. RESULTS: Three hundred and four patients received 2-4 courses of the HDMTX plus additional chemotherapy, and delayed MTX elimination was observed in 165 courses of 127 patients. In those, nephrotoxicity was significantly correlated with plasma MTX levels for each patient (P = 0.03), and also for each course (P = 0.009), but no other toxicities were correlated. Another analysis according to HDMTX courses showed no significant correlation between the first high plasma MTX levels and subsequent MTX levels in later course. It also showed that incidence of liver and gastrointestinal toxicities was most frequent in the first HDMTX course, and then sharply decreased in later courses (P < 0.001). CONCLUSIONS: Our results suggest that plasma MTX level is not a reliable predictor for adverse events except for nephrotoxicity in multiple HDMTX therapy courses in childhood B-NHL. Pediatr Blood Cancer 2015;62:279-284. © 2014 Wiley Periodicals, Inc.

Prognostic model for predicting overall survival in children and adolescents with rhabdomyosarcoma.

BACKGROUND: The purpose of this study was to develop a prognostic model for the survival of pediatric patients with rhabdomyosarcoma (RMS) using parameters that are measured during routine clinical management. METHODS: Demographic and clinical variables were evaluated in 1679 pediatric patients with RMS registered in the Surveillance, Epidemiology, and End Results (SEER) program from 1990 to 2010. A multivariate Cox proportional hazards model was developed to predict median, 5-year and 10-year overall survival (OS). The Akaike information criterion technique was used for model selection. A nomogram was constructed using the reduced model after model selection, and was internally validated. RESULTS: Of the total 1679 patients, 543 died. The 5-year OS rate was 64.5% (95% confidence interval (CI), 62.1-67.1%) and the 10-year OS was 61.8% (95%CI, 59.2-64.5%) for the entire cohort. Multivariate analysis identified age at diagnosis, tumor size, histological type, tumor stage, surgery and radiotherapy as significantly associated with survival (p < 0.05). The bootstrap-corrected c-index for the model was 0.74. The calibration curve suggested that the model was well calibrated for all predictions. CONCLUSIONS: This study provided an objective analysis of all currently available data for pediatric RMS from the SEER cancer registry. A nomogram based on parameters that are measured on a routine basis was developed. The nomogram can be used to predict 5- and 10-year OS with reasonable accuracy. This information will be useful for estimating prognosis and in guiding treatment selection.

Novel swine model of transfusion-related acute lung injury.

BACKGROUND: Transfusion-related acute lung injury (TRALI) is a life-threatening complication of blood transfusion. Antibodies against human leukocyte antigens in donors' plasma are the major causes of TRALI. Several animal models of TRALI have been developed, and the mechanism underlying TRALI development has been extensively investigated using rodent models. Although sheep models of nonimmune TRALI have been developed, large-animal models of antibody-mediated TRALI are not yet available. STUDY DESIGN AND METHODS: To develop a swine model of TRALI, male Clawn strain miniature pigs were used. A monoclonal antibody (MoAb) against swine leukocyte antigens (SLAs) Class I (4G8, 0.3 or 1.0 mg/kg body weight [BW]) and a control antibody (1.0 mg/kg BW) were injected into the peripheral vein after priming with or without 1 µg/kg BW lipopolysaccharide (LPS; n = 3 each). Lung injury was assessed using PaO2 /FiO2 (P/F) ratio and by chest X-ray imaging. Histopathologic analysis was also conducted. RESULTS: Lung injury could be induced by injecting 4G8 at an amount of 1.0 mg/kg BW, after LPS. The P/F ratio 90 minutes after the administration of 4G8 significantly decreased (p < 0.05). Bilateral infiltration was shown in chest X-ray imaging. Lung injury was confirmed by histopathologic analysis. CONCLUSION: Lung injury in pigs was successfully induced by anti-SLA MoAb. Priming with LPS is a prerequisite for inducing lung injury and the amount of the antibody is a critical condition.

Hepatocytes buried in the cirrhotic livers of patients with biliary atresia proliferate and function in the livers of urokinase-type plasminogen activator-NOG mice.

The pathogenesis of biliary atresia (BA), which leads to end-stage cirrhosis in most patients, has been thought to inflame and obstruct the intrahepatic and extrahepatic bile ducts. BA is not believed to be caused by abnormalities in parenchymal hepatocytes. However, there has been no report of a detailed analysis of hepatocytes buried in the cirrhotic livers of patients with BA. Therefore, we evaluated the proliferative potential of these hepatocytes in immunodeficient, liver-injured mice [the urokinase-type plasminogen activator (uPA) transgenic NOD/Shi-scid IL2rγnull (NOG); uPA-NOG strain]. We succeeded in isolating viable hepatocytes from the livers of patients with BA who had various degrees of fibrosis. The isolated hepatocytes were intrasplenically transplanted into the livers of uPA-NOG mice. The hepatocytes of only 3 of the 9 BA patients secreted detectable amounts of human albumin in sera when they were transplanted into mice. However, human leukocyte antigen-positive hepatocyte colonies were detected in 7 of the 9 mice with hepatocyte transplants from patients with BA. We demonstrated that hepatocytes buried in the cirrhotic livers of patients with BA retained their proliferative potential. A liver that was reconstituted with hepatocytes from patients with BA was shown to be a functioning human liver with a drug-metabolizing enzyme gene expression pattern that was representative of mature human liver and biliary function, as ascertained by fluorescent dye excretion into the bile canaliculi. These results imply that removing the primary etiology via an earlier portoenterostomy may increase the quantity of functionally intact hepatocytes remaining in a cirrhotic liver and may contribute to improved outcomes.

Improved treatment results of children with B-cell non-Hodgkin lymphoma: a report from the Japanese Pediatric Leukemia/Lymphoma Study Group B-NHL03 study.

BACKGROUND: Previous Japanese studies of childhood B-cell non-Hodgkin lymphoma (B-NHL) have shown a favorable outcome, though the study size was too small to effectively assess the efficacy and safety of treatment for childhood B-NHL. PROCEDURE: We performed a nation-wide prospective B-NHL03 study to assess the efficacy and safety of short-pulse intensive chemotherapy for children with B-NHL. They were stratified into four treatment groups according to disease stage, tumor resectability and bone marrow/CNS involvement: Group 1 with all resected stage I/II, Group 2 with non-resected stage I/II, Group 3 with stage III & CNS-negative stage IV, and Group 4 with CNS-positive stage IV & Burkitt leukemia. Treatment duration was 2 courses for Group 1, 4 courses for Group 2, and 6 courses for Groups 3 and 4, respectively. CNS irradiation was omitted in all patients. RESULTS: The follow-up time ranged from 0.8 to 88 months, with a median of being 45 months. For 321 patients analyzed in this study, overall survival and event-free survival (EFS) at 4 years was 92.7% and 87.4%, respectively. The 4-year EFS according to treatment group were 94% for Group 1 (n = 17), 98% for Group 2 (n = 103), 84% for Group 3 (n = 111), and 78% for Group 4 (n = 90). There was no significant difference in outcome by histology. Therapy-related death occurred in three patients in remission. CONCLUSIONS: Our nationwide large-scale study resulted in a cure rate above 90% with <1% toxic death in childhood B-NHL.

Significance of CD66c expression in childhood acute lymphoblastic leukemia.

Upon analyzing 696 childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL) cases, we identified the characteristics of CD66c expression. In addition to the confirmation of strong correlation with BCR-ABL positivity and hyperdiploid, we further observed that CD66c is frequently expressed in CRLF2-positive (11/15, p<0.01 against chimeric gene-negative) as well as hypodiploid cases (3/4), whereas it is never expressed in ETV6-RUNX1, MLL-AF4, MLL-AF9, MLL-ENL, and E2A-PBX1-positive cases. Although the expression of CD66c itself is not directly linked to the prognosis, the accompanying genetic abnormalities are important prognostic factors for BCP-ALL, indicating the importance of CD66c expression in the initial diagnosis of BCP-ALL.

Clinical initiatives linking Japanese and Swedish healthcare resources on cancer studies utilizing Biobank Repositories.

The Tokyo Medical University Hospital in Japan and the Lund University hospital in Sweden have recently initiated a research program with the objective to impact on patient treatment by clinical disease stage characterization (phenotyping), utilizing proteomics sequencing platforms. By sharing clinical experiences, patient treatment principles, and biobank strategies, our respective clinical teams in Japan and Sweden will aid in the development of predictive and drug related protein biomarkers. Data from joint lung cancer studies are presented where protein expression from Neuro- Endocrine lung cancer (LCNEC) phenotype patients can be separated from Small cell- (SCLC) and Large Cell lung cancer (LCC) patients by deep sequencing and spectral counting analysis. LCNEC, a subtype of large cell carcinoma (LCC), is characterized by neuroendocrine differentiation that small cell lung carcinoma (SCLC) shares. Pre-therapeutic histological distinction between LCNEC and SCLC has so far been problematic, leading to adverse clinical outcome. An establishment of protein targets characteristic of LCNEC is quite helpful for decision of optimal therapeutic strategy by diagnosing individual patients. Proteoform annotation and clinical biobanking is part of the HUPO initiative (http://www.hupo.org) within chromosome 10 and chromosome 19 consortia.

DNA methylation profile distinguishes clear cell sarcoma of the kidney from other pediatric renal tumors.

A number of specific, distinct neoplastic entities occur in the pediatric kidney, including Wilms' tumor, clear cell sarcoma of the kidney (CCSK), congenital mesoblastic nephroma (CMN), rhabdoid tumor of the kidney (RTK), and the Ewing's sarcoma family of tumors (ESFT). By employing DNA methylation profiling using Illumina Infinium HumanMethylation27, we analyzed the epigenetic characteristics of the sarcomas including CCSK, RTK, and ESFT in comparison with those of the non-neoplastic kidney (NK), and these tumors exhibited distinct DNA methylation profiles in a tumor-type-specific manner. CCSK is the most frequently hypermethylated, but least frequently hypomethylated, at CpG sites among these sarcomas, and exhibited 490 hypermethylated and 46 hypomethylated CpG sites in compared with NK. We further validated the results by MassARRAY, and revealed that a combination of four genes was sufficient for the DNA methylation profile-based differentiation of these tumors by clustering analysis. Furthermore, THBS1 CpG sites were found to be specifically hypermethylated in CCSK and, thus, the DNA methylation status of these THBS1 sites alone was sufficient for the distinction of CCSK from other pediatric renal tumors, including Wilms' tumor and CMN. Moreover, combined bisulfite restriction analysis could be applied for the detection of hypermethylation of a THBS1 CpG site. Besides the biological significance in the pathogenesis, the DNA methylation profile should be useful for the differential diagnosis of pediatric renal tumors.