Induction of hypoxia-inducible factor-1α inhibits drug-induced apoptosis in the human leukemic cell line HL-60

BACKGROUND

Leukemic cells originate from hypoxic bone marrow, which protects them from anti-cancer drugs. Although many factors that cause drug resistance in leukemic cells have been studied, the effect of hypoxia on drug-induced apoptosis is still poorly understood.

METHODS

In this study, we examined the effect of hypoxia on anti-leukemic drug resistance in leukemic cell lines treated with cobalt chloride (CoCl(2)), a hypoxia-mimetic agent. Cellular proliferation was evaluated using the methyl thiazolyl tetrazolium (MTT) assay. Flow cytometry analysis and western blots were performed to investigate apoptosis-related proteins.

RESULTS

Unlike its previously known apoptotic effect, the expression of HIF-1α increased the survival rate of human promyelocytic leukemia HL-60 cells when these cells were exposed to anti-leukemic drugs; these effects were mediated by heat-shock protein HSP70 and the pro-apoptotic protein Bax.

CONCLUSION

These findings may provide new insights for understanding the mechanisms underlying hypoxia and for designing new therapeutic strategies for acute myeloid leukemia.

Dexrazoxane for preventing anthracycline cardiotoxicity in children with solid tumors

This study attempted to assess the incidence and outcome of anthracycline cardiotoxicity and the role of dexrazoxane as a cardioprotectant in childhood solid tumors. The dexrazoxane group included 47 patients and the control group of historical cohort included 42. Dexrazoxane was given in the 10:1 ratio to doxorubicin. Fractional shortening and systolic and diastolic left ventricular diameters were used to assess the cardiac function. The median follow-ups were 54 months in the dexrazoxane group and 86 months in the control group. The mean cumulative doses of doxorubicin were 280.8+/-83.4 mg/m(2) in the dexrazoxane group and 266.1+/-75.0 mg/m(2) in the control group. The dexrazoxane group experienced significantly fewer cardiac events (27.7% vs. 52.4%) and less severe congestive heart failure (6.4% vs. 14.3%) than the control group. Thirteen cardiotoxicities including one cardiac death and 2 congestive heart failures occurred in the dexrazoxane group, and 22 cardiotoxicities including 2 cardiac deaths and 4 congestive heart failures, in the control group. Five year cardiac event free survival rates were 69.2% in the dexrazoxane group and 45.8% in the control group (P=0.04). Dexrazoxane reduces the incidence and severity of early and late anthracycline cardiotoxicity in childhood solid tumors.

The outcome of hematopoietic stem cell transplantation in Korean children with hemophagocytic lymphohistiocytosis

Chemoimmunotherapy-based treatments have improved the survival of patients with HLH, but outcomes of the patients are still unsatisfactory. We report here the outcome of Korean children with HLH who underwent HSCT, which was analyzed from the data of a nation-wide HLH registry. Retrospective nation-wide data recruitment for the pediatric HLH patients diagnosed between 1996 and 2008 was carried out by the Histiocytosis Working Party of the Korean Society of Hematology. Nineteen patients who received HSCT among the total of 148 enrolled children with HLH were analyzed for the transplant-related variables and events. The probability of five-yr survival after HSCT was 73.3% with a median follow-up of 57. Two months compared to 54.3% for the patients who were treated with chemoimmunotherapy only (p = 0.05). The reasons for HSCT were active disease after eight wk of initial treatment (n = 9), relapsed disease (n = 5), and FHL (n = 5). Fourteen patients are currently alive without disease after HSCT, four patients died of treatment-related events (infection in two and graft failure in two) at early post-transplant period, and one patient died of relapse at one yr post transplantation. The survival of patients who were transplanted because of active disease after eight wk of initial treatment was worse compared to those patients who had inactive state at that time (60.6% vs. 100%, respectively, p = 0.06). Of the four patients who received transplants using cord blood, three died of graft failure (n = 2) and relapse (n = 1). The five-yr probability of survival after HSCT according to the donor type was 85.7% for the MRDs (n = 6), 87.5% for the MUDs (n = 8), and 40% for the MMUDs (n = 5) (p = 0.03). Other variables such as age, CNS involvement at the time of diagnosis, the etiology of HLH (familial or secondary), and the conditioning regimens had no influence on the five-yr OS of the HLH patients who underwent HSCT. HSCT improved the survival of the patients who had familial, relapsed, or severe and persistent SHLH in the Korean nation-wide HLH registry. Although numbers were small, these results are similar to other reports in the literature. The disease state after initial treatment, the stem cell source of the transplant, and the donor type were the important prognostic factors that affected the OS of the HLH patients who underwent HSCT.

Eye-preserving therapy in retinoblastoma: prolonged primary chemotherapy alone or combined with local therapy

Purpose

To evaluate the efficacy of primary chemotherapy combined with local therapy in the treatment of retinoblastomas not treatable with a single therapeutic method.

Methods

We performed a retrospective chart review of 227 patients diagnosed with retinoblastoma. Sixty-five eyes in 52 patients had tumors not treatable with a single therapeutic method and received primary chemotherapy combined with local therapy as needed.

Results

Tumor control and eye salvage was achieved in 34 of the 65 eyes; the probability of ocular survival was 46.56% using the Kaplan-Meier method. Forty-three of the 65 eyes were group D or E tumors, in which tumor control and eye salvage was achieved in 16 eyes. Twenty eyes were treated with chemotherapy only, while 28 eyes received one additional modality of local therapy, and 17 eyes received two modalities of local therapy. Of the eyes treated with chemotherapy only, tumor control was achieved in 5 eyes.

Conclusions

Primary chemotherapy combined with local therapy can be effective and safe in the treatment of retinoblastomas otherwise untreatable with other therapeutic methods, such as group D and E retinoblastomas. More vigorous treatment with more local therapeutic methods combined may yield even better results.

Long-term outcomes in children with glioblastoma

OBJECT

Glioblastoma is the most common primary malignant brain tumor; however, glioblastoma in children is less common than in adults, and little is known about its clinical outcome in children. The authors evaluated the long-term outcome of glioblastoma in children.

METHODS

Twenty-seven children were confirmed to have harbored a glioblastoma between 1985 and 2007. The clinical features and treatment outcomes were reviewed retrospectively. All patients underwent resection; complete resection was performed in 12 patients (44%), subtotal resection in 12 patients (44%), and biopsy in 3 patients (11%). Twenty-four patients (89%) had radiation therapy, and 14 (52%) patients received chemotherapy plus radiation therapy. Among the latter, 5 patients had radiation therapy concurrent with temozolomide chemotherapy. Four patients with small-size recurrent glioblastoma received stereotactic radiosurgery.

RESULTS

The median overall survival (OS) was 43 months, and the median progression-free survival was 12 months. The OS rate was 67% at 1 year, 52% at 2 years, and 40% at 5 years. The median OS was significantly associated with tumor location (52 months for superficially located tumors vs 7 months for deeply located tumors; p = 0.017) and extent of removal (106 months for completely resected tumors vs 11 months for incompletely resected tumors; p < 0.0001).

CONCLUSIONS

The prognosis of glioblastoma is better in children than in adults. Radical resection followed by concurrent chemoradiation therapy may be the initial treatment of choice.

Efficacy of high-dose chemotherapy and autologous stem cell transplantation in patients with relapsed medulloblastoma: a report on the Korean Society for Pediatric Neuro-Oncology (KSPNO)-S-053 study

The efficacy and toxicity of high-dose chemotherapy and autologous stem cell transplantation (HDCT/ASCT) were investigated for improving the outcomes of patients with relapsed medulloblastoma. A total of 15 patients with relapsed medulloblastoma were enrolled in the KSPNO-S-053 study from May 2005 to May 2007. All patients received approximately 4 cycles of salvage chemotherapy after relapse. Thirteen underwent HDCT/ASCT; CTE and CM regimen were employed for the first HDCT (HDCT1) and second HDCT (HDCT2), respectively, and 7 underwent HDCT2. One transplant related mortality (TRM) due to veno-occlusive disease (VOD) occurred during HDCT1 but HDCT2 was tolerable with no further TRM. The 3-yr overall survival probability and event-free survival rates +/-95% confidence intervals (CI) were 33.3+/-12.2% and 26.7% +/-11.4%, respectively. When analysis was confined to only patients who had a complete response (CR) or partial response (PR) prior to HDCT, the probability of 3-yr overall survival rates +/-95% CI was 40.0+/-15.5%. No patients with stable disease (SD) or progressive disease (PD) survived. Survival rates from protocol KSPNO-S-053 are encouraging and show that tumor status prior to HDCT/ASCT is an important factor to consider for improving survival rates of patients with relapsed medulloblastoma.

FK506 causes cellular and functional defects in human natural killer cells

The role of NK cells in allogeneic HCT has been increasingly appreciated, particularly in the GVL effect. Although FK506 has been used widely to prevent GVHD, its action was considered to be primarily through activated T cells. In this study, we provide direct evidence for the first time that human NK cells are immediate targets of FK506. Our in vivo data from patients undergoing peripheral blood stem cell transplantation or BMT showed a reduced number of NK cells with down-regulated CD25 expression in their peripheral blood compartment. Likewise, FK506 caused profound inhibition of NK cell proliferation in vitro and suppressed NK cytotoxicity and cytokine secretion in response to IL-2. These defects were accompanied by impaired cell clustering and selective down-regulation of adhesion molecules, ICAM-1, CD2, CD49d, and CD58. Furthermore, FK506 specifically inhibited expression of NKG2D, CD48, and DNAM1 receptors without affecting that of 2B4, NKp30, NKp44, and NKp46. As a result, natural cytotoxicity against K562 tumor targets was impaired, while leaving redirected ADCC via 2B4 intact. Finally, FK506-treated NK cells showed impaired IL-2R signaling and inhibition of STAT3. Collectively, these signaling impairments and selective down-regulation of NK receptors by FK506 may underlie the proliferative and functional defects of NK cells. Thus, our data provide a new insight into the mechanism of immunosuppression by FK506, which should be considered to interpret the outcome of graft transplantation.

Weekly rituximab followed by monthly rituximab treatment for steroid-refractory chronic graft-versus-host disease: results from a prospective, multicenter, phase II study

BACKGROUND

Since it was suggested that B cells play a role in the pathogenesis of chronic graft-versus-host disease, rituximab, an anti-CD20 monoclonal antibody targeting B cells, has been shown to be effective in steroid-refractory, chronic graft-versus-host disease. However, most of the data were from small numbers of patients or retrospective analyses. We, therefore, conducted a multicenter phase II study to confirm the efficacy of this treatment strategy that targets B cells.

DESIGN AND METHODS

We diagnosed and evaluated chronic graft-versus-host disease according to the National Institute of Health criteria for clinical trials on this condition. The treatment consisted of weekly intravenous infusions of rituximab for 4 weeks followed by monthly rituximab for 4 months. We evaluated the patients' responses and monitored their disease activity until their final visit, which was on day 365. We also assessed the patients' subsequent quality of life and serum levels of B-cell-activating factor of the tumor necrosis factor family.

RESULTS

Among 37 patients enrolled (median age, 29 years; range 8-57 years), 32 patients responded to rituximab with 8 complete and 24 partial responses. Twenty-one patients maintained their response for 1 year, so their steroid treatment was discontinued or its dose reduced (21/37, or 56.8%), and their scores representing quality of life were improved although these changes were not statistically significant. The responses were better for clinical manifestations of the skin, oral cavity and musculoskeletal system (response rate, 71.4-100%) than for other organs. However, infectious complications and primary disease relapse accounted for the majority of treatment failure. The pre-treatment serum level of B cell-activating factor of the tumor necrosis factor family was not associated with better treatment outcome (P=0.147).

CONCLUSIONS

Rituximab could improve clinical responses and quality of life of patients with steroid-refractory chronic graft-versus-host disease, although such patients may need active prophylaxis against infection.

Reduced-dose craniospinal radiotherapy followed by high-dose chemotherapy and autologous stem cell rescue for children with newly diagnosed high-risk medulloblastoma or supratentorial primitive neuroectodermal tumor

Background

In this study, we investigated the effects of reduced-dose craniospinal radiotherapy (CSRT) followed by tandem high-dose chemotherapy (HDCT) with autologous stem cell rescue (ASCR) in children with a newly diagnosed high-risk medulloblastoma (MB) or supratentorial primitive neuroectodermal tumor (sPNET).

Methods

Between March 2005 and April 2007, patients older than 3 years with a newly diagnosed high-risk MB or sPNET were enrolled. The patients received two cycles of pre-RT chemotherapy consisting of cisplatin, etoposide, vincristine, and cyclophosphamide (cycle A), and carboplatin, etoposide, vincristine, and ifosphamide (cycle B), followed by CSRT with 23.4 Gy and local RT with 30.6 Gy. After four cycles of post-RT chemotherapy (cycles A, B, A, and B), tandem double HDCT with ASCR was performed.

Results

A total of 13 patients (MB=11, sPNET=2) were enrolled. Of these, one patient progressed, one patient died of septic shock after the second cycle of B, and one patient relapsed after the third cycle of B. The 3-year event-free survival (EFS) rate of the patients intended for HDCT was 76.9%, whereas the 3-year EFS rate of the patients who received HDCT was 100%. No treatment-related mortality occurred during HDCT.

Conclusion

Although the follow-up period was short and the patient cohort was small in size, the results of this study are encouraging. The limited toxicity and favorable EFS rate observed in children treated with reduced-dose CSRT followed by HDCT and ASCR warrant further exploration in a larger study population.

High transcript level of FLT3 associated with high risk of relapse in pediatric acute myeloid leukemia

Identification of prognostic factors and risk-based post-remission therapy was proposed to improve the outcomes of acute myeloid leukemia (AML) and a mutation of FLT3 has been reported to be a risk factor, especially for pediatric patients. Recently, FLT3 expression level was implicated to have prognostic significance in adults, but little is known for childhood AML. To define the prognostic significance, transcript level of FLT3 was analyzed in 52 pediatric AML patients. The median copy number of FLT3 was 4.6x10(3) (40-5.9x10(7) copies)/1.0x10(6) GAPDH copy, and the relapse free survival of patients with high transcript level of FLT3 (>10(6) copy number) (0%) was significantly lower than that of the others (53.2%). High transcript level of FLT3 was associated with a markedly high risk of relapse. The development of new therapeutic scheme such as a frontline allogeneic stem cell transplantation or administration of FLT3 inhibitor is needed to improve outcomes.

Double umbilical cord blood transplantation for children and adolescents

Umbilical cord blood transplantation (UCBT) with two units has been conducted with promising results in adults to overcome the limitation of low cell numbers. In an attempt to improve the outcomes, double UCBT was performed in children and adolescents. Sixty-one patients, including 44 acute leukemia, and 17 other hematologic diseases, received double UCBT. Donor-type engraftment achieved in 82% of patients. Except one patient with persistent mixed chimerism of two units, other 49 patients showed dominancy of one unit and only the CFU-GM was significant factor influencing dominancy. The event-free survival (EFS) of leukemia and other hematologic disease were 59% and 53%, respectively, and the EFS of acute leukemia patients who received transplant in first or second CR (68.6%) was significantly better than in those with advanced disease (22.2%) (P = 0.007). Among the factors influencing outcomes, low cell dose difference between two units (TNC difference/TNC of large unit <15%) were associated with higher TRM, relapse, and lower EFS. Double UCBT was a promising modality of transplant in children and adolescence. However, engraftment and other results were not so satisfactory yet. To improve the outcomes, development of new selection guideline, probably including cell dose difference between two units and technology to enhance engraftment and reduce transplantation-related mortality are warranted.

Polymorphisms in innate immunity genes and risk of childhood leukemia

The immune system plays an important role in the control of cancer development. To investigate possible genetic contribution to childhood leukemia risk in the innate immune system, we performed an association study for the 1214 SNPs in 146 gene regions related to innate immunity using GoldenGate (Illumina) oligonucleotide pool assay (OPA) in 106 case patients and 123 controls. Childhood leukemia risk was estimated as odds ratios and 95% confidence intervals adjusted for age, gender and birth weight. The minP test was used to identify statistically significant association at gene level. Three SNPs (STAT6 rs703817, C1qG rs17433222, and MBP rs3794845) were significantly associated with childhood leukemia risk (p(trend) < 0.001, minP < 0.01). The most significant association with childhood leukemia risk was for STAT6 rs703817 (GA vs GG: 0.48 (0.26-0.87), AA vs GG: 0.21 (0.07-0.61), p(trend) = 0.0003, minP = 0.002). Subgroup analysis showed that Ly96 rs78380171 and MBP rs3794845 were significantly associated with the risk of acute lymphoblastic leukemia (p(trend) < 0.001). Our results suggest that genetic polymorphisms in innate immunity genes might play a role in the genesis of childhood leukemia with limited biologic evidence. Additional, larger studies are needed to identify the mechanism of these genes in childhood leukemia patients.

Efficacy of tandem high-dose chemotherapy and autologous stem cell rescue in patients over 1 year of age with stage 4 neuroblastoma: the Korean Society of Pediatric Hematology-Oncology experience over 6 years (2000-2005)

The efficacy of tandem high-dose chemotherapy and autologous stem cell rescue (HDCT/ASCR) was investigated in patients with high-risk neuroblastoma. Patients over 1 yr of age who were newly diagnosed with stage 4 neuroblastoma from January 2000 to December 2005 were enrolled in The Korean Society of Pediatric Hematology-Oncology registry. All patients who were assigned to receive HDCT/ASCR at diagnosis were retrospectively analyzed to investigate the efficacy of single or tandem HDCT/ASCR. Seventy and 71 patients were assigned to receive single or tandem HDCT/ASCR at diagnosis. Fifty-seven and 59 patients in the single or tandem HDCT group underwent single or tandem HDCT/ASCR as scheduled. Twenty-four and 38 patients in the single or tandem HDCT group remained event free with a median follow-up of 56 (24-88) months. When the survival rate was analyzed according to intent-to-treat at diagnosis, the probability of the 5-yr event-free survival+/-95% confidence intervals was higher in the tandem HDCT group than in the single HDCT group (51.2+/-12.4% vs. 31.3+/-11.5%, P=0.030). The results of the present study demonstrate that the tandem HDCT/ASCR strategy is significantly better than the single HDCT/ASCR strategy for improved survival in the treatment of high-risk neuroblastoma patients.

Abstract 2846: SNPs in apoptosis and cell cycle control related genes and brain tumor risk among children in Korea

Objective

In a hospital-based case-control study in Korea, we evaluated the association between polymorphisms in genes involved in apoptosis and cell cycle control and brain tumor risk among children.

Methods

Incident brain tumor cases (n=70) and non-cancer controls (n=254) were recruited from three teaching hospitals in Seoul between May 2003 and August 2006. Information on the characteristics of children and their parents were collected by trained interviewers using structured questionnaire. Tagging single-nucleotide polymorphisms (SNPs) were selected using a pairwise linkage-disequilibrium (LD) based algorithm (n=304) were genotyped for 43 cases and 153 controls in this study. Odds ratios (ORs) and 95% confidence intervals (CIs) for SNP genotypes were estimated using unconditional logistic regression adjusted for age and birth weight. The false discovery rate (FDR) was estimated to evaluate the probability of false positive associations; we considered FDR &lt;0.2 as noteworthy.

Results

Eleven tag SNPs in six genes, AICDA, LMO2, MYC, BCL2, BCL2A1, and CASP7 were significantly associated with childhood brain tumor (Ptrend&lt;0.05). Two SNPs (rs12306110 and rs3794318) in AICDA gene, encoding activation-induced cytidine deaminase, remained significant after adjusting of multiple tests. These SNPs were in tight LD. The most significant association with childhood brain tumor risk was for the rs12306110 (OR, 0.24; 95% CI, 0.11-0.51).

ConclusionOur results suggest that genetic polymorphisms in AICDA may be associated with the risk of brain tumor in childhood.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2846.

Abstract 925: Common variants in genes related to immune response and childhood leukemia risk

Objective: In order to investigate possible genetic contribution to childhood leukemia in the immune system, we evaluated the associations between 786 SNPs in 68 genes/gene regions related to immune response and childhood leukemia risk.

Methods: Incident childhood leukemia cases (n=136) and non-cancer controls (n=254) were recruited from three teaching hospitals in Seoul between 2003 and 2006. Candidate genes/gene regions were selected based on SNP databases (CGAP and SNP500 database), and genotype assay was performed using GoldenGate (Illumina) oligonucleotide pool assay (OPA). First, we selected SNPs with dose response effect (Ptrend&lt;0.001). The 16 SNPs deemed unusable due to failure of genotyping or monomorphism (9 SNPs), low yield (2 SNPs), HWE p &lt;0.001 (5 SNPs) in each case and control were excluded from the analysis. A gene-level minP was computed using a permutation-based re-sampling procedure (10,000 permutations) taking all SNPs in each gene/gene region into account. We considered minP &lt;0.05 as noteworthy. Childhood leukemia risk was estimated as odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for age, gender and birth weight.

Results: Among the 786 SNPs, 134 SNPs in 7 genes/gene regions were significantly associated with childhood leukemia risk (Ptrend &lt;0.001). Five out of 7 genes/gene regions of immune response (MDM2 (murine double minute 2), CD81 (CD81 molecule), IL-2 (interleukin 2), TNF/LTA (tumor necrosis factor-a (TNF) and lymphotoxin-a), RELB (v-rel reticuloendotheliosis viral oncogene homolog B)) were significantly associated with childhood leukemia risk (minP &lt;0.01).

Discussion: Our results suggest that genetic polymorphisms in immune regulatory may play a role in childhood leukemia development. Further large study is warranted confirm our findings.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 925.

Abstract 1825: Maternal alcohol consumption and childhood acute myeloid leukemia risk

Background: Leukemia is the most common malignancy in children. The etiology of childhood leukemia is mostly unknown, although some environmental factors such as ionizing radiation and parental alcohol and tobacco use may play a causative role in leukemia.

Methods: To investigate the association between parental alcohol consumption and childhood leukemia in a hospital-based case-control study in Korea, histologically-confirmed incident childhood leukemia cases (n=365) aged 0-18 years old were recruited from three teaching hospitals located in Seoul, Korea, between May 2003 and August 2008. Non-cancer controls (n=558) aged 0-18 years old without medical history of childhood cancer were recruited from the Department of Pediatrics of the same hospitals. Controls were frequency-matched to cases by 5-year age intervals and sex (cases: controls=1:1). Leukemia risks were estimated as odds ratios (ORs) and 95% confidence intervals (CIs) using unconditional logistic regression analysis adjusted for age, sex, parent's education, and birth weight (&lt;3.25, 3.25-3.70, ≥3.70 kg). In addition to conducting analyses of all childhood leukemia, we calculated histologic subtype-specific ORs for acute lymphoblastic leukemia (ALL; n=200) and acute myeloid leukemia (AML; n=88).

Results: Among general characteristics, higher birth weight and parental education were associated with childhood leukemia risk (P&lt;0.05). The proportion of drinking mothers was significantly higher among all leukemia cases than controls (58% vs. 49%: OR=1.4, 95% CI=1.00-1.83), whereas no association was observed for paternal alcohol consumption (87% vs. 83%). When the analysis was restricted to AML cases, the association between maternal drinking and cancer risk became stronger (OR=1.8, 95% CI=1.06-2.90). Drinking frequency of the mothers was also associated with the increased risk. (≥1/month vs. &lt;1/month; OR=1.7, 95% CI=1.10-2.28). Also, drinking duration of more than one year before pregnancy increased the risk of AML (OR=1.7, 95% CI= 1.00-2.85). No association was found between parental alcohol consumption and ALL risk.

Conclusion: Our results suggest that maternal alcohol consumption is associated with AML among Korean children. However, larger studies need to be conducted to replicate our findings.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1825.

Genome-wide association study of childhood acute lymphoblastic leukemia in Korea

We conducted a genome-wide association study of childhood acute lymphoblastic leukemia (ALL) in a case-control study conducted in Korea. Incident childhood ALL cases (n=50) and non-cancer controls (n=50) frequency-matched to cases by age and sex, recruited from three teaching hospitals in Seoul between 2003 and 2008, were genotyped using Affymetrix SNP Array 6.0 platform. ALL risks were estimated as odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for age and birth weight. The false discovery rate (FDR) was used for adjusting multiple tests. Of these 1 million SNPs, six SNPs in 4 genes (HAO1 rs6140264, EPB41L2 rs9388856, rs9388857, rs1360756, C2orf3 12105972, MAN2A1 rs3776932) were strongly associated with childhood ALL risk (P(dominant)<or=0.0001 and P(trend)<0.006). These SNPs remained significant after FDR adjustment (FDR value <0.2). Our genome-wide association study in Korea children identified a few genetic variations as potential susceptibility markers for ALL, warranting further replication studies among various ethnic groups.

Association of human leukocyte antigen class II alleles with response to immunosuppressive therapy in Korean aplastic anemia patients

HLA-DR15 (DR2) is overrepresented in aplastic anemia (AA) patients, and its presence is associated with a better response to cyclosporine-based immunosuppressive therapy (IST). However, little is known about other human leukocyte antigen (HLA) alleles affecting therapy response. We investigated 37 Korean patients with severe AA for the association of HLA class II alleles with response to IST: cyclosporine A combined with antithymocyte globulin or antilymphocyte globulin. Molecular or serologic typing of HLA-DR and HLA-DQ alleles was performed. In responders (13/37, 35.1%), the frequency of HLA-DR15 was increased (69.2% vs 8.3%, p = 0.0002) and that of DR4 was decreased (7.7% vs 66.7%, p = 0.0007) compared with nonresponders. The response rate was significantly higher in DR15(+) than in DR15(-) (81.8% vs 15.4%, p = 0.0002) and in DR4(-) than in DR4(+) patients (60.0% vs 5.9%, p = 0.0007). The response rates in the best (DR15(+)/DR4(-)), intermediate, and poor response groups (DR15(-)/DR4(+)) were 88.9, 38.5, and 0%, respectively (p = 0.00001). At the allelic level, DRB1*1501 and closely linked DQB1*0602 were associated with a good response and DRB1*0405 and closely linked DQB1*0401 with a poor response to IST. HLA-DR typing may be useful for predicting a response to IST in AA patients.

Idarubicin plus behenoyl cytarabine and 6-thioguanine compares favorably with idarubicin plus cytarabine-based regimen for children with previously untreated acute myeloid leukemia: 10-year retrospective, multicenter study in Korea

We investigated the outcome of idarubicin plus N(4)-behenoyl-1-beta-D-arabinofuranosyl cytosine (BHAC)-based chemotherapy (BHAC group, n=149) compared to idarubicin plus cytarabine-based chemotherapy (cytarabine group, n=191) for childhood acute myeloid leukemia (AML). Between January 1996 and December 2005, 340 children with AML from 5 university hospitals in Korea received the BHAC-based or cytarabine-based chemotherapy, with or without hematopoietic stem cell transplantation. After induction therapy, 264 (77.6%) of 340 children achieved a complete remission (CR) and 43 (12%) achieved a partial remission (PR). The CR rate in the BHAC group was higher than in the cytarabine group (85.2% vs. 71.7%, P=0.004). However, the overall response rate (CR+PR) was not different between the two groups (93.3% vs. 87.9%, P=0.139). The 5-yr estimates of overall survival (OS) of children in the two groups were similar (54.9% for the BHAC group vs. 52.4% for the cytarabine group, P=0.281). Although the results were analyzed according to the treatment type and cytogenetic risk, the OS showed no significant difference between the BHAC group and the cytarabine group. In the present study, the clinical outcomes of the BHAC-based chemotherapy, consisting of BHAC, idarubicin, and 6-TG, are comparable to that of the cytarabine-based chemotherapy for childhood AML.

UNC13D is the predominant causative gene with recurrent splicing mutations in Korean patients with familial hemophagocytic lymphohistiocytosis

BACKGROUND

Familial hemophagocytic lymphohistiocytosis is a fatal disease characterized by immune dysregulation from defective function of cytotoxic lymphocytes. Three causative genes have been identified for this autosomal recessive disorder (PRF1, UNC13D, and STX11). We investigated the molecular genetics of familial hemophagocytic lymphohistiocytosis in Korea.

DESIGN AND METHODS

Pediatric patients who fulfilled the HLH-2004 criteria were recruited from the Korean Registry for Histiocytosis. Molecular genetic studies were performed on the patients' DNA samples by direct sequencing of all coding exons and flanking sequences of PRF1, UNC13D, and STX11.

RESULTS

Forty patients were studied and familial hemophagocytic lymphohistiocytosis mutations were identified in nine; eight patients had UNC13D mutations (89%) and one had a mutation in PRF1. No patient had a STX11 mutation. Notably, four patients had only one UNC13D mutant allele, suggesting that the other mutation was missed by conventional direct sequencing. All UNC13D mutations were deleterious in nature. One known splicing mutation, c.754-1G>C, was recurrent, accounting for 58% of all the mutant alleles (7/12). Five UNC13D mutations were novel (p.Gln98X, p.Glu565SerfsX7, c.1993-2A>G, c.2367+1G>A, and c.2954+5G>A). The one patient with PRF1 mutation was homozygous for a frameshift mutation (p.Leu364GlufsX93), which was previously reported to be the most frequent PRF1 mutation in Japan.

CONCLUSIONS

This is the first investigation on the molecular genetics of familial hemophagocytic lymphohistiocytosis in Korea. The data showed that UNC13D is the predominant causative gene in the Korean population. The identification of mutations missed by conventional sequencing would better delineate the mutation spectrum and help to establish the optimal molecular diagnostic strategy for familial hemophagocytic lymphohistiocytosis in Korea, which might need an RNA-based screening strategy.

Hepatic veno-occlusive disease in children after hematopoietic stem cell transplantation: incidence, risk factors, and outcome

Four hundred and sixty-seven hematopoietic stem cell transplantations (HSCTs) (217 autologous and 250 allogeneic HSCT) were performed in 374 children at four pediatric HSCT centers in Korea from January 2005 to December 2007. Among 467 transplants, veno-occlusive disease (VOD) developed in 72 transplants (15.4%) at a median of 10 days after HSCT. Multivariate analysis showed that BU or TBI-containing regimen (P=0.002), VOD prophylaxis without lipo-prostaglandin E1 (PGE1) (P=0.012), number of previous HSCT (P=0.014), and pretransplant serum ferritin (P=0.018) were independent risk factors for developing VOD. Mean serum ferritin levels were significantly higher in HSCT with VOD (2109.6+/-2842.5 ng/ml) than in HSCT without VOD (1315.9+/-1094.4 ng/ml) (P<0.001). The relative risk of death within 100 days of HSCT in transplants with VOD compared with transplants without VOD was 3.39 (confidence interval: 1.78-6.45). Our results suggest that lipo-PGE1 might have a protective effect against the development of VOD, and pretransplant serum ferritin could act as a risk factor for VOD. A larger prospective study is needed to confirm a possible role of lipo-PGE1 and iron chelation therapy in reducing the incidence of VOD.

Concurrent langerhans cell histiocytosis and B-lineage lymphoid proliferation in the bone marrow

We present three cases of concurrent Langerhans cell histiocytosis (LCH) and B-lineage lymphoid cell infiltrations and/or nodules in the bone marrow. The first patient was a 25-month-old boy who presented with LCH on the right shoulder and multiple osteolytic lesions. Bone marrow biopsy showed the presence of LCH and two large lymphoid nodules of B-lineage, which were located in the paratrabecular region. Both LCH and the lymphoid nodules resolved after treatment with prednisone, vinblastine, methotrexate, and cyclophosphamide. The second patient was a 7-month-old girl who presented with LCH in the scalp and bone marrow. In spite of the treatment, a follow-up bone marrow analysis performed after 16 months showed LCH and increased B-lineage lymphoid cells in the interstitial area. The third patient was a 26-month-old girl, and imaging studies revealed reddish skin lesions and multiple osteolytic lesions. Skin biopsy and bone marrow biopsy did not show the presence of LCH; however, we initiated the treatment on the basis of the results of imaging studies. The follow-up study after 6 months showed the presence of LCH and large, patchy infiltration of B-lymphoid cells. We report three rare cases of concurrent bone marrow involvement of LCH and B-lineage lymphoid proliferation, which strongly suggest lymphoid malignancy. Further, clonal changes should be studied to elucidate the common pathogenic mechanism between the two diseases.

Initial response to treatment was highly associated with the prognosis of childhood rhabdomyosarcoma: a retrospective analysis of a single center experience in Korea

PURPOSE

Following the introduction of a multimodal approach to diagnosis and treatment, the prognosis of rhabdomyosarcoma (RMS) has markedly improved over the last three decades. However, there are few data on treatment outcomes in Korean patients.

MATERIALS AND METHODS

We performed a retrospective analysis of 77 patients with RMS diagnosed and treated at Seoul National University Children's Hospital between 1986 and 2005.

RESULTS

The overall 5-year survival and event-free survival rates for all patients were 77% and 59%, respectively. The Intergroup Rhabdomyosarcoma Study clinical grouping and initial response to treatment (20-week response) were important prognostic factors.

CONCLUSIONS

The outcome of childhood RMS was closely associated with the initial staging and the initial response to treatment. Modulating therapies according to initial responses and risk factors is critical, and new treatment strategies for high-risk patients are needed.

Successful salvage unrelated umbilical cord blood transplantation with two units after engraftment failure with single unit in severe aplastic anemia

Severe aplastic anemia (SAA) patients without an HLA-matched sibling donor need alternative treatment options. Umbilical cord blood transplantation (UCBT) has become an alternative means for treating various diseases, but it has not been proved to be a satisfactory method to treat SAA. Here, we report the case of a girl who underwent successful two-unit UCBT after engraftment failure with a single unit. Two-unit UCBT is proposed to have better engraftment potential and to offer a better chance of survival, according to some reports. Increased cell dose and graft-versus-graft reaction could contribute to these advantages. With this promising result, two-unit UCBT could be an alternative treatment option for patients with SAA without an HLA-matched donor.