Epidemiologic and Clinical Outcomes of Pediatric Renal Tumors in Korea: A Retrospective Analysis of The Korean Pediatric Hematology and Oncology Group (KPHOG) Data.

PURPOSE: Renal tumors account for approximately 7% of all childhood cancers. These include Wilms tumor (WT), clear cell sarcoma of the kidney (CCSK), malignant rhabdoid tumor of the kidney (MRTK), renal cell carcinoma (RCC), congenital mesoblastic nephroma (CMN) and other rare tumors. We investigated the epidemiology of pediatric renal tumors in Korea. MATERIALS AND METHODS: From January 2001 to December 2015, data of pediatric patients (0-18 years) newly-diagnosed with renal tumors at 26 hospitals were retrospectively analyzed. RESULTS: Among 439 patients (male, 240), the most common tumor was WT (n=342, 77.9%), followed by RCC (n=36, 8.2%), CCSK (n=24, 5.5%), MRTK (n=16, 3.6%), CMN (n=12, 2.7%), and others (n=9, 2.1%). Median age at diagnosis was 27.1 months (range 0-225.5) and median follow-up duration was 88.5 months (range 0-211.6). Overall, 32 patients died, of whom 17, 11, 1, and 3 died of relapse, progressive disease, second malignant neoplasm, and treatment-related mortality. Five-year overall survival and event free survival were 97.2% and 84.8% in WT, 90.6% and 82.1% in RCC, 81.1% and 63.6% in CCSK, 60.3% and 56.2% in MRTK, and 100% and 91.7% in CMN, respectively (p < 0.001). CONCLUSION: The pediatric renal tumor types in Korea are similar to those previously reported in other countries. WT accounted for a large proportion and survival was excellent. Non-Wilms renal tumors included a variety of tumors and showed inferior outcome, especially MRTK. Further efforts are necessary to optimize the treatment and analyze the genetic characteristics of pediatric renal tumors in Korea.

Usefulness of Routine Coagulation Tests in Healthy Children Undergoing Elective Minor Surgery: a 12-Year Retrospective Study.

BACKGROUND: Although routine coagulation tests, such as prothrombin time (PT) and activated partial thromboplastin time (aPTT) are performed before surgery to identify the risk of perioperative bleeding, bleeding complications are rare in minor surgeries, and false-positive results are often observed. Therefore, this study aimed to analyze the common causes of abnormal results of preoperative coagulation tests in previously healthy children undergoing elective minor surgery and determine the usefulness of performing these tests. Additionally, it aimed to identify the distribution of factor XII activity in children with prolonged aPTT. METHODS: The medical records of 363 pediatric patients aged 0 - 18 years, who were referred to the pediatric hematology-oncology department due to abnormal preoperative coagulation tests prior to undergoing minor surgery at the Kyung Hee University Medical Center between March 2008 and October 2020, were retrospectively review-ed. RESULTS: The majority of patients (n = 348, 96%) had prolonged aPTT, few (n = 29, 8%) had a prolonged PT international normalized ratio, and a small number (n = 14, 4%) had both prolonged PT and aPTT. On repeating the coagulation tests, 194 children showed persistent abnormal results. Of these, 184 patients underwent mixing tests, and 176 showed correction for factor deficiency (n = 26) and lupus anticoagulant positive (n = 14). Factor deficiencies included factor XII (n = 16), possibility of von Willebrand disease (vWD; n = 4), factor XI (n = 2), factor VIII (n = 1), factors IX and XII (n = 1), factor VII (n = 1), and factor V (n = 1). The severity of factor deficiency was mild (25 - 38%). One patient with factor VII deficiency received preoperative clotting factors but had postoperative bleeding requiring clotting factor replacement. Another patient with possible vWD received fresh frozen plasma after surgery and had mild symptoms. Linear regression showed no significant correlation between factor XII activity and aPTT in patients with prolonged aPTT (R2 = 0.0002, p = 0.84) or factor XII activity according to aPTT results in those with factor XII deficiency (R2 = 0.04749, p = 0.40). CONCLUSIONS: These results suggest that coagulation tests may be selectively performed in previously healthy children undergoing minor surgery with positive bleeding and/or family history. The distribution of factor XII should be investigated further.

Serum cytokine profiles in infants with infantile hemangiomas on oral propranolol treatment: VEGF and bFGF, potential biomarkers predicting clinical outcomes.

BACKGROUND: Oral propranolol has become first-line treatment for infantile hemangiomas (IHs). This study focused on identifying cytokines related to the biology of IH and early regression indicators of IH after propranolol treatment. METHODS: For inclusion, the patients had to be aged less than 1 year and have an IH with a largest diameter ≥2 cm. Patients were scheduled to receive 1 year of propranolol treatment. Serum cytokines involved in angiogenesis, vasculogenesis, and/or chronic inflammation were analyzed at 0, 1, and/or 12 months after treatment using Multiplex Luminex assays. RESULTS: Among the 49 evaluable patients, 33 completed the 1-year treatment: 16 showed excellent response and 12 had good response to propranolol. Significant decreases in serum MMP-2, bFGF, VEGF-α, and MCP-1 levels were observed after 1 year of treatment compared to pretreatment values. The maximal diameters of the lesions significantly correlated with pretreatment serum VEGF-α, bFGF, and MMP-9. Patients with higher bFGF and VEGF levels showed better response to propranolol at 1 year. CONCLUSION: MMP-2, VEGF-α, bFGF, and MCP-1 may involve in the biology of IH and their downregulation may be associated with involution processes of IH. Pretreatment bFGF and VEGF could be novel biomarkers for predicting response to propranolol. IMPACT: We found that decreases in the concentrations of MMP-2, bFGF, VEGF, and MCP-1 were associated with regression of the hemangioma, which indicates that one of the mechanisms of propranolol in the treatment of proliferative hemangiomas may involve downregulation of those cytokines. Patients with higher bFGF and VEGF levels showed better response to propranolol at 1 year. Importantly, serum bFGF higher than 37.07 pg/mL may predict an excellent response to propranolol. Therefore, along with the patient's age and the size and visual characteristics of the lesion, bFGF levels could help determine the viability of propranolol use in the treatment of IHs. Our study represented extensive serum profiling in IH, reporting the indicators and molecules clearly related to IH regression with propranolol treatment. The authors believe that monitoring serum cytokines, including MMP-2, bFGF, VEGF, and MCP-1, in IH patients could be important, in addition to clinical follow-up, for determining when to start and end propranolol treatment.

Prospective case control study of iron deficiency and the risk of febrile seizures in children in South Korea.

BACKGROUND: Febrile seizures are the most common type of seizure in the first 5 years of life, and many factors that increase seizure risk have been identified. This study was performed to examine the association between iron status and febrile seizures in children in South Korea. METHODS: A prospective unmatched case control study was performed in 63 cases of febrile seizures and 65 controls with febrile illness but no seizures. RESULTS: Serum iron, plasma ferritin, and transferrin saturation were significantly lower in children with febrile seizures compared to the controls. Iron deficiency, defined as ferritin < 30 ng/mL, was more prevalent in the febrile seizure group (49.2%) than in the control group (16.9%). Serum iron < 22 ng/dL (odds ratio 3.42, 95% confidence interval [CI] 1.31-8.9, P = 0.012) and ferritin < 30 ng/mL (odds ratio 6.18, 95% CI 2.32-16.42, P < 0.001) were associated with increased risk of developing febrile seizures in multivariate logistic regression analysis. CONCLUSION: These observations suggest that iron deficiency prior to development of anemia may increase risk of febrile seizures.

Langerhans Cell Histiocytosis of the Gastrointestinal Tract: Evidence for Risk Organ Status.

OBJECTIVE: To investigate the "risk status" of Langerhans cell histiocytosis (LCH) of the gastrointestinal tract. STUDY DESIGN: Outcomes from 43 published cases of patients with LCH and gastrointestinal tract involvement were matched to 43 patients with LCH without gastrointestinal tract involvement cared for at our institution. Comparisons were made of the 5-year overall survival rates determined from Kaplan-Meier survival curves for the entire cohort of patients, as well as subgroups defined by lack of risk organ involvement and later era of treatment (to control for temporal changes in LCH treatment regimens). In addition, an association between LCH-gastrointestinal tract and risk organ involvement was investigated. RESULTS: The 5-year overall survival for children with LCH-gastrointestinal tract (45.3%) was significantly worse than for those without gastrointestinal tract involvement (94.6%; P = .001). This difference remained significant after we excluded risk organ involvement (53.6%% vs 100%; P = .001), and analyzing subjects diagnosed after 2000 (75% vs 100%; P = .012). A 4-fold increase in risk organ involvement with LCH-gastrointestinal tract was observed (OR 4.359; 95% CI 1.75-10.82, P = .001). CONCLUSIONS: This limited retrospective study suggests that patients with LCH-gastrointestinal tract involvement may have decreased survival, independent of risk organ involvement, and provides evidence to support a prospective study to evaluate risk organ status of LCH-gastrointestinal tract. LCH-gastrointestinal tract may be associated with a 4-fold risk for risk organ involvement. Attention to gastrointestinal symptoms and LCH-gastrointestinal tract in young children diagnosed with LCH is warranted.

Risk Factor Analysis for Secondary Malignancy in Dexrazoxane-Treated Pediatric Cancer Patients.

PURPOSE: Dexrazoxane has been used as an effective cardioprotector against anthracycline cardiotoxicity. This study intended to analyze cardioprotective efficacy and secondary malignancy development, and elucidate risk factors for secondary malignancies in dexrazoxane-treated pediatric patients. MATERIALS AND METHODS: Data was collected from 15 hospitals in Korea. Patients who received any anthracyclines, and completed treatment without stem cell transplantation were included. For efficacy evaluation, the incidence of cardiac events and cardiac event-free survival rates were compared. Data about risk factors of secondary malignancies were collected. RESULTS: Data of total 1,453 cases were analyzed; dexrazoxane with every anthracyclines group (D group, 1,035 patients) and no dexrazoxane group (non-D group, 418 patients). Incidence of the reported cardiac events was not statistically different between two groups; however, the cardiac event-free survival rate of patients with more than 400 mg/m2 of anthracyclines was significantly higher in D group (91.2% vs. 80.1%, p=0.04). The 6-year cumulative incidence of secondary malignancy was not different between both groups after considering follow-up duration difference (non-D, 0.52%±0.37%; D, 0.60%±0.28%; p=0.55). The most influential risk factor for secondary malignancy was the duration of anthracycline administration according to multivariate analysis. CONCLUSION: Dexrazoxane had an efficacy in lowering cardiac event-free survival rates in patients with higher cumulative anthracyclines. As a result of multivariate analysis for assessing risk factors of secondary malignancy, the occurrence of secondary malignancy was not related to dexrazoxane administration.

Higher Gemcitabine Dose Was Associated With Better Outcome of Osteosarcoma Patients Receiving Gemcitabine-Docetaxel Chemotherapy.

BACKGROUND: Efficacy of gemcitabine and docetaxel (GEM + DOC) chemotherapy in patients with recurrent or refractory osteosarcoma was evaluated. METHODS: Data of 53 patients from 9 institutions, who received GEM (675 or 900 mg/m(2) on days 1 and 8) and DOC (100 mg/m(2) on day 8), were retrospectively reviewed. RESULTS: GEM + DOC was administered as adjuvant (n = 25) or palliative chemotherapy (n = 28). Patients received a median 3 courses (range, 1-10 courses). Objective response rate (CR + PR, where CR is complete response and PR is partial response) and disease control rate (CR+ PR + SD, where SD is stable disease) were 14.3% and 28.6%, respectively. Disease control rate was higher in patients receiving 900 mg/m(2) GEM than in patients receiving 675 mg/m(2) (50.0% vs. 12.5%, P = 0.03). Higher GEM dose was associated with better survival, both in adjuvant (1-year overall survival, 90.9 ± 8.7% vs. 38.5 ± 13.5%, P = 0.002) and palliative settings (50.0 ± 14.4% vs. 31.3 ± 11.6%, P = 0.04). CONCLUSIONS: Further studies are necessary to investigate the efficacy of more aggressive and higher doses of GEM + DOC chemotherapy in osteosarcoma.

Should healthy children who will undergo minor surgery be screened for coagulation disorder?

The objective of this study is to analyze the major causes of abnormal findings seen in the preoperative coagulation tests of asymptomatic pediatric patients and to discuss the usefulness of coagulation tests prior to minor surgery. Among patients who received minor surgery in Kyung Hee University Medical Center from March 2008 to April 2015, a total of 7114 pediatric patients (ages 1-18) were included in our study. Of these, 226 (3.1%) were referred to the pediatrics hematology-oncology department because of abnormal preoperative coagulation tests. A review of the coagulation tests indicate the majority (n = 216, 95.5%) have prolonged activated partial thromboplastin time (aPTT), whereas a smaller number (n = 10, 4.5%) have prolonged prothrombin time international normalized ratio (PT INR). When the coagulation tests were repeated, 136 displayed abnormal findings again. Of these 136 patients, 128 patients underwent mixing tests, and 127 showed results of correction and were composed as follows: normal (n = 83), subnormal (n = 26), factor deficiency (n = 15), and lupus anticoagulant positive (n = 3). Breakdown by factor deficiencies was as follows: (i) factor XII (n = 9), (ii) factor IX (n = 2), (iii) factors XII and IX (n = 1), (iv) factor VIII (n = 1), (v) factor XI (n = 1), (vi) von Willebrand factor (vWF; n = 1), and (vii) factor V (n = 1). Each factor activity range was mild (21%-39%), so no patients received preoperative medications or clotting factors/blood products. Even in the presence of factor deficiencies, bleeding symptoms were mild and postoperative complications did not occur. These results suggest that coagulation tests may not be needed in healthy children and should be reserved for patients with positive bleeding and/or family history.

Decreased Cystatin C-Estimated Glomerular Filtration Rate Is Correlated with Prolonged Hospital Stay in Transient Tachypnea of Newborn Infants.

BACKGROUND: Transient tachypnea of the newborn (TTN) is a benign disorder with a variable clinical course that often leads to hospitalization. The aim of this study was to assess and validate the relationship between the serum cystatin C level and symptom duration in infants with TTN. METHODS: Forty newborns presenting with TTN and who had undergone serum cystatin C (Cys C) tests on the first day of admission to the Kyung Hee University Hospital (Seoul, Korea) from 2009 to 2013 were included. The serum Cys C level, creatinine (Cr) level, estimated glomerular filtration rate (eGFR), and tachypnea duration were correlated retrospectively. RESULTS: The median gestation period was 37.8 ± 3.8 weeks and the mean birth weight was 3.2 ± 0.4 kg. Tachypnea duration was 3.3 ± 2.0 days. Serum Cys C and Cr levels were 1.7 ± 0.2 mg/L and 0.8 ± 1.2 mg/dL, respectively. Tachypnea duration was significantly positively correlated with the serum levels of Cys C and significantly negatively correlated with Cys C-based eGFR (p = 0.016), but was not significantly correlated with the serum Cr level or Cr-based eGFR. When tachypnea duration was compared between infants with Cys C level <1.6 mg/L (n = 15; Group A) and infants with Cys C level ≥ 1.6 mg/L (n = 25; Group B), the symptom duration was significantly shorter in Group A infants (p = 0.011). CONCLUSION: Tachypnea duration was shorter with higher Cys C-based eGFR in infants with TTN.

Hepatic angiosarcoma mimicking congenital cytomegalovirus infection in an infant with thrombocytopenia.

Hepatic angiosarcomas are uncommon, highly aggressive tumors, rarely seen in children. A 3-month-old female infant was admitted to hospital for evaluation of multiple petechiae on her body. She had hepatosplenomegaly and scattered petechiae over her entire body. Laboratory tests indicated thrombocytopenia and positive cytomegalovirus (CMV) polymerase chain reaction. Ganciclovir was started, and the platelet count increased. After 4 months the patient was readmitted to hospital for drowsy mental status and eventually died from severe bleeding. Needle biopsy of the liver was performed after receiving written consent from the parents. Pathological findings of the liver lesion included features consistent with hepatic angiosarcoma. There have been no previous reports of hepatic angiosarcoma in Korean infants. Here, we report an infant with hepatosplenomegaly and thrombocytopenia who was diagnosed with hepatic angiosarcoma mimicking congenital CMV infection.

Clinical features, genetics, and outcome of pediatric patients with hemophagocytic lymphohistiocytosis in Korea: report of a nationwide survey from Korea Histiocytosis Working Party.

BACKGROUND: We analyzed a nationwide registry of pediatric patients with hemophagocytic lymphohistiocytosis (HLH) in Korea to assess the clinical and genetic features and treatment outcomes in pediatric HLH. METHODS: The Korea Histiocytosis Working Party retrospectively analyzed data on 251 pediatric patients diagnosed with HLH between 1996 and 2011. RESULTS: In the study cohort, 25 cases were categorized with familial HLH, 64 with presumed secondary HLH, and 162 with unspecified HLH. Of 217 evaluable patients, 91 (42%) had concomitant Epstein-Barr virus infection. Of 238 evaluable patients, central nervous system (CNS) involvement, which was more frequent in the familial group, was evident in 81 cases (34%). Genetic tests revealed a predominant UNC13D mutation with a high incidence of two recurrent splicing mutations (c.118-308C>T and c.754-1G>C). The 5-yr overall survival rate was 68% (38% in the familial group and 81% in the presumed secondary group). The 5-yr overall survival rate among 32 patients who underwent allogeneic hematopoietic stem cell transplantation was 64%. In multivariate analysis, a younger age at diagnosis, severe transaminasemia, and a coagulation abnormality were independent prognostic factors for survival. Responses during initial treatments were also significant indicators of outcome. CONCLUSION: Our study showed the unique predominance of a UNC13D mutation and vulnerability to Epstein-Barr virus infection in Korean children with HLH and emphasizes the prognostic significance of age, liver dysfunction, and treatment responses in this disease. A multicenter prospective trial that builds on the present results is warranted to identify subgroups of patients with a poor prognosis and identify optimal treatments.

Antibody ligation of CM1 on cisplatin-exposed HeLa cells induces apoptosis through reactive oxygen species-dependent Fas ligand expression.

Centrocyte/centroblast marker 1 (CM1) has been identified as a pro-apoptosis molecule on B-cell lymphoma cells as well as several types of cancer cells. In this study, we investigated its signaling mechanism in HeLa cells after treatment with cisplatin in order to potentially identify a new therapeutic target. The CM1 molecule was induced on the surface of cisplatin-exposed HeLa cells. In these cells, ligation of CM1 with anti-CM1 monoclonal antibodies inhibited cell proliferation and produced reactive oxygen species. Fas ligand (FasL) expression was upregulated without upregulating Fas in cisplatin-exposed HeLa cells after CM1 stimulation. Pretreatment with N-acetylcysteine, a pan-capase inhibitor, and ZB4, an antagonistic anti-Fas antibody, effectively inhibited the apoptotic effect triggered by CM1. CM1 ligation induced apoptosis through disruption of the mitochondrial membrane potential, decreased Bcl-2 and phosphorylated ERK expression. These findings identify CM1 as a potential new therapeutic target related to cisplatin-exposed cervical cancer.

Clinical features and treatment outcomes of Langerhans cell histiocytosis: a nationwide survey from Korea histiocytosis working party.

A nationwide survey was conducted to clarify the clinical features and outcomes of Korean children with Langerhans cell histiocytosis (LCH). Korea Histiocytosis Working Party analyzed the data of 603 patients who were diagnosed with LCH between 1986 and 2010 from 28 institutions in Korea. Median age at diagnosis was 65 months (range, 0 to 276 mo). Bone was the most frequently affected organ (79.6%) followed by skin (19.2%). Initially, 419 patients (69.5%) had single-system involvement (SS), 85 (14.1%) with multisystem (MS) disease without risk organ involvement (MS-RO), and 99 (16.4%) multisystem disease with risk organ involvement (MS-RO). The 5-year overall survival (OS) rates in the SS, MS-RO, and MS-RO groups were 99.8%, 98.4%, and 77.0%, respectively (P<0.001), and the 5-year reactivation rates were 17.9%, 33.5%, and 34.3%, respectively (P<0.001). The OS rate was lower in patients with RO involvement (P=0.025) and lack of response to initial treatment (P=0.001). MS involvement (P=0.036) was an independent risk factor for reactivation. Permanent consequences were documented in 99 patients (16.4%). Reactivation of disease, MS involvement, and age at diagnosis ≤ 2 years were associated with higher incidence of permanent consequences. This study emphasized that further efforts are required to improve survival of MS-RO patients and reduce reactivation in younger patients with MS involvement.

A comparison of logistic regression analysis and an artificial neural network using the BI-RADS lexicon for ultrasonography in conjunction with introbserver variability.

To determine which Breast Imaging Reporting and Data System (BI-RADS) descriptors for ultrasound are predictors for breast cancer using logistic regression (LR) analysis in conjunction with interobserver variability between breast radiologists, and to compare the performance of artificial neural network (ANN) and LR models in differentiation of benign and malignant breast masses. Five breast radiologists retrospectively reviewed 140 breast masses and described each lesion using BI-RADS lexicon and categorized final assessments. Interobserver agreements between the observers were measured by kappa statistics. The radiologists' responses for BI-RADS were pooled. The data were divided randomly into train (n = 70) and test sets (n = 70). Using train set, optimal independent variables were determined by using LR analysis with forward stepwise selection. The LR and ANN models were constructed with the optimal independent variables and the biopsy results as dependent variable. Performances of the models and radiologists were evaluated on the test set using receiver-operating characteristic (ROC) analysis. Among BI-RADS descriptors, margin and boundary were determined as the predictors according to stepwise LR showing moderate interobserver agreement. Area under the ROC curves (AUC) for both of LR and ANN were 0.87 (95% CI, 0.77-0.94). AUCs for the five radiologists ranged 0.79-0.91. There was no significant difference in AUC values among the LR, ANN, and radiologists (p > 0.05). Margin and boundary were found as statistically significant predictors with good interobserver agreement. Use of the LR and ANN showed similar performance to that of the radiologists for differentiation of benign and malignant breast masses.

A rare case of microgranular acute promyelocytic leukemia associated with ider(17)(q10)t(15;17) in an old-age patient.

We present a rare case of microgranular variant acute promyelocytic leukemia (APL) associated with ider(17)(q10)t(15;17)(q22;q12) of an old-age patient. The initial chromosome study showed a 46,XX,del(6)(?q21q25),der(15)t(15;17)(q22;q12),ider(17)(q10)t(15;17)[10]/47,sl,+ider(17)(q10)t(15;17)[3]/46,XX[16]. FISH signals from a dual color dual fusion translocation PML-RARA probe were consistent with the results of conventional cytogenetics. Because of the rarity of ider(17)(q10)t(15;17) in microgranular APL, further studies on both gene dosage effect of this chromosomal abnormality and the influence of ider(17)(q10)t(15;17) on clinical features such as prognosis, survival, and treatment response of APL cases are recommended.

A case of anemia caused by combined vitamin B12 and iron deficiency manifesting as short stature and delayed puberty.

Anemia caused by vitamin B12 deficiency resulting from inadequate dietary intake is rare in children in the modern era because of improvements in nutritional status. However, such anemia can be caused by decreased ingestion or impaired absorption and/or utilization of vitamin B12. We report the case of an 18-year-old man with short stature, prepubertal sexual maturation, exertional dyspnea, and severe anemia with a hemoglobin level of 3.3 g/dL. He had a history of small bowel resection from 50 cm below the Treitz ligament to 5 cm above the ileocecal valve necessitated by midgut volvulus in the neonatal period. Laboratory tests showed deficiencies of both vitamin B12 and iron. A bone marrow examination revealed dyserythropoiesis and low levels of hemosiderin particles, and a cytogenetic study disclosed a normal karyotype. After treatment with parenteral vitamin B12 and elemental iron, both anemia and growth showed gradual improvement. This is a rare case that presented with short stature and delayed puberty caused by nutritional deficiency anemia in Korea.

ider(17)(q10)t(15;17) associated with relapse and poor prognosis in a pediatric patient with acute promyelocytic leukemia.

Although acute promyelocytic leukemia (APL) has been regarded as a serious medical emergency associated with disseminated intravascular coagulopathy or subsequent mortality, it is now considered a curable leukemia that is particularly sensitive to treatment with all-trans retinoic acid combined with chemotherapy. However, it is not clear whether additional chromosomal abnormalities in APL patients directly influence the prognosis or treatment response. ider(17)(q10)t(15;17)(q22;q21) has mostly been reported in adult APL patients, and only three cases of pediatric APL associated with ider(17)(q10)t(15;17) showing poor prognosis have been described in the literature. Here, we report the close follow-up (clinical and laboratory) data of a pediatric APL case associated with ider(17)(q10)t(15;17). This patient had APL relapse from the same clone 15 months after morphological remission. Furthermore, despite subsequent chemotherapy, the patient died 16 months after the initial APL diagnosis. Although based on a limited amount of data (four pediatric APL cases), such results in pediatric APL patients may provide important insight into the relationship between ider(17)(q10)t(15;17) and poor prognosis. However, further well-designed case-control studies are necessary to determine the treatment response and prognosis in pediatric or adult APL patients with ider(17)(q10)t(15;17).