The Relationship Between Duration of Stay and Self-rated Health Among International College Students in South Korea.

This study examined relationships between duration of stay and self-rated health among international students in South Korea and compared participants' health-related characteristics according to duration of stay. The study recruited a convenience sample of 165 international students enrolled in undergraduate or graduate programs. For this cross-sectional, descriptive study, participants were recruited at one South Korean university. Data were subjected to ordinal logistic regression analyses. After controlling for covariates, a stay of 6 months or less was a significant predictor of better self-rated health. Compared to those in their first semester, international students staying more than 6 months more frequently experienced short sleep duration, physical health symptoms, healthcare utilization, unmet healthcare needs, and perceived discrimination. Study findings indicate that international students' health tends to deteriorate after their first semester. To promote the health and academic success of international students, universities should provide timely health promotion programs.

E-learning cultural competence for public health workers: A feasibility and pilot study.

OBJECTIVE: To describe the development, feasibility, and preliminary efficacy of a seven-module e-learning for enhancing cultural competence of public health workers. DESIGN: The study was based on the framework of the new Medical Research Council; a mixed methods design was used. SAMPLE: A four-week pilot cluster-randomized controlled trial was conducted with 39 public health workers and 74 migrants in South Korea. Feasibility and preliminary efficacy were assessed according to initiation, retention, adherence, usability, acceptability, individual and organizational cultural competence, and migrant trust and satisfaction. Quantitative data were collected at baseline, 4 weeks, and 12 weeks. Focus group interviews were conducted with eight public health workers at 12 weeks. RESULTS: Initiation, retention, and adherence rates were high. Participants agreed on acceptability, but exhibited mixed results on usability. Participants were satisfied with "well-structured content," "authentic case stories and videos," "increased interest in migrant care," and "opportunity for self-reflection." However, "flawless and trouble-free system," "screen design for easy navigation," "instructor's expertise," and "more situational cases and videos" were desired. Statistically significant differences were observed for individual cultural competence, migrant trust, and satisfaction. CONCLUSION: Generally, the intervention seems feasible and has preliminary efficacy, yet usability improvement is necessary for full-scale randomized controlled trials.

Experience of migrant care and needs for cultural competence training among public health workers in Korea.

OBJECTIVE: This study explored the experiences of public health workers (PHWs) providing health care for migrants living in Korea and clarified needs for cultural competence training. DESIGN AND SAMPLE: Twenty-six PHWs from five public health centers in Gwangju city, South Korea, participated in this exploratory qualitative study. METHODS: Five semi-structured focus group interviews of PHWs were conducted from September to December 2016. A directed content analysis approach was conducted using four categories: perceived characteristics of migrants, interaction between PHWs and migrants, interaction between PHWs and organizations/systems, and cultural competence training needs. RESULTS: PHWs perceived that migrants lacked autonomy in health decisions and awareness of health behaviors. PHWs experienced difficulties in communicating and in establishing trusting relationships. They found clients hard to reach and easy to miss, a lack of continuity in health care programs, and inadequate human and material resources. They preferred passive teaching methods to activity-based simulation. PHWs believed essential training should be provided through e-learning to all PHWs, including management. CONCLUSION: PHWs reported experiencing multiple challenges from a lack of preparedness for culturally competent care and their clients' vulnerability. Development of cultural competence training is suggested through e-learning that reflects the PHWs' experiences and provides systematic support.

TALEN-mediated single-base-pair editing identification of an intergenic mutation upstream of BUB1B as causative of PCS (MVA) syndrome.

Cancer-prone syndrome of premature chromatid separation with mosaic variegated aneuploidy [PCS (MVA) syndrome] is a rare autosomal recessive disorder characterized by constitutional aneuploidy and a high risk of childhood cancer. We previously reported monoallelic mutations in the BUB1B gene (encoding BUBR1) in seven Japanese families with the syndrome. No second mutation was found in the opposite allele of any of the families studied, although a conserved BUB1B haplotype and a decreased transcript were identified. To clarify the molecular pathology of the second allele, we extended our mutational search to a candidate region surrounding BUB1B. A unique single nucleotide substitution, G > A at ss802470619, was identified in an intergenic region 44 kb upstream of a BUB1B transcription start site, which cosegregated with the disorder. To examine whether this is the causal mutation, we designed a transcription activator-like effector nuclease-mediated two-step single-base pair editing strategy and biallelically introduced this substitution into cultured human cells. The cell clones showed reduced BUB1B transcripts, increased PCS frequency, and MVA, which are the hallmarks of the syndrome. We also encountered a case of a Japanese infant with PCS (MVA) syndrome carrying a homozygous single nucleotide substitution at ss802470619. These results suggested that the nucleotide substitution identified was the causal mutation of PCS (MVA) syndrome.

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.

Predictors of Posttraumatic Stress Symptoms Among Adolescent and Young Adult Survivors of Childhood Cancer: Importance of Monitoring Survivors' Experiences of Family Functioning.

The purpose of this study was to identify factors associated with posttraumatic stress symptoms (PTSS) among Japanese long-term childhood cancer survivors (CCSs). Subjects comprised 185 adolescent and young adult (AYA) CCSs who completed anonymous self-report questionnaires. Attending physicians also completed an anonymous disease/treatment data sheet. Mean age of survivors was approximately 8 years at diagnosis and 23 years at participation. Multiple regression analysis showed that family functioning, satisfaction with social support, being female, and interactions between family functioning and gender and age at the time of diagnosis were associated with PTSS among survivors. This study revealed family functioning as the most predictive factor of PTSS among AYA CCSs in Japan. Even when the survivor may have unchangeable risk factors, family functioning can potentially moderate the effects on PTSS. Thus, it is crucial for health professionals to carefully monitor and attend to survivors' experiences of family functioning to mitigate PTSS.

General health status and late effects among adolescent and young adult survivors of childhood cancer in Japan.

OBJECTIVE: We sought to investigate general health status and late effects among adolescent and young adult survivors of childhood cancer. METHODS: We conducted a cross-sectional survey, using self-rated questionnaires on current and past health problems. Questionnaires were provided to childhood cancer survivors, a comparison group of siblings and a general population control group that was recruited online. χ(2) tests were used to compare responses to the 72 survey items. RESULTS: The final sample included 185 childhood cancer survivors (72% response rate), 72 siblings and 1000 general population controls. In the childhood cancer survivors group, the median age of diagnosis was 8 years and the median age at survey was 23 years. According to the physicians' reports, 56% of the childhood cancer survivors experienced at least one late effect. In descending order of prevalence, the current symptoms in the childhood cancer survivors group were (i) impaired visual acuity (45%), (ii) dizziness (36%) and (iii) any allergy (34%). The three most common symptoms had similar prevalence rates in each of the groups. As compared with the control group, the following physical symptoms were significantly more common in the childhood cancer survivors group: mental retardation (odds ratio: 48.6, P < 0.01); cataract (odds ratio: 29.7); suspected infertility (odds ratio: 25.1); delayed puberty (odds ratio 24.9); growth hormone deficiency (odds ratio: 23.0); and other audiovisual, urinary, endocrine, infertility, cardiovascular, respiratory, gastrointestinal, spinal, extremity and neuromuscular problems. CONCLUSIONS: Many adolescent/young adult childhood cancer survivors could be suffering from ongoing late effects that stem from cancer and its treatment. Overall health monitoring for childhood cancer survivors can provide indispensable benefits.

Assessment of corticosteroid-induced osteonecrosis in children undergoing chemotherapy for acute lymphoblastic leukemia: a report from the Japanese Childhood Cancer and Leukemia Study Group.

Steroid-induced osteonecrosis (ON) is a challenging complication encountered during modern chemotherapy for childhood acute lymphoblastic leukemia (ALL). We retrospectively assessed the incidence of ON and its risk factors in a total of 1095 patients enrolled in 3 consecutive Japanese Children's Cancer and Leukemia Study Group ALL studies (ALL941 [1994 to 2000], n=464; ALL2000 [2000 to 2004], n=305; and ALL2004 [2004 to 2010], n=326). ON was diagnosed in 16 patients, of whom 15 were symptomatic. The cumulative incidence of ON was 0.76% in ALL941, 0.35% in ALL2000, and 3.6% in ALL2004. The incidence of ON in ALL941/2000, in which only prednisolone was administered as a steroid, was significantly lower than that in ALL2004, in which dexamethasone was used as a partial substitute for prednisolone (P<0.01). In ALL2004, sex and age were significantly correlated with the incidence of ON (1.3% in boys vs. 6.7% in girls, P=0.0132; 0.42% for age <10 y vs. 15.6% for age ≥10 y, P<0.0001), suggesting that girls aged 10 years and above are at a greater risk of ON onset. These results indicate that the risk of ON should be considered when administering dexamethasone as part of ALL protocol treatment in girls aged 10 years and above.

IKZF1 and CRLF2 gene alterations correlate with poor prognosis in Japanese BCR-ABL1-negative high-risk B-cell precursor acute lymphoblastic leukemia.

BACKGROUND: Genome-wide analysis studies have demonstrated that IKZF1, CRLF2, and JAK2 gene alterations correlate with poor prognosis in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). However, the prognostic significance for these gene alterations has not been clarified in Japanese patients. PROCEDURE: A total of 194 patients with BCP-ALL enrolled in the Japanese Children's Cancer & Leukemia Study Group ALL 2004 clinical trial were assessed for the presence of three different gene alterations: IKZF1 deletions, CRLF2 expression and JAK2 mutation. RESULTS: IKZF1 deletions and CRLF2-high expression were identified in 22 of 177 (12%) patients and in 15 of 141 (11%) patients, respectively. However, JAK2 R683 mutation was detected only one of 177 patients. The 4-year event-free survival (4y-EFS) was different when comparing patients with or without IKZF1 deletions (68.2% vs. 85.2%; P = 0.04) and was also different when comparing patients with different CRLF2 expression levels (high, 66.7% vs. low, 88.1%; P = 0.03). The differences in 4y-EFS were statistically significant in patients with ALL in the National Cancer Institute (NCI)-high risk group (HR-ALL) (IKZF1 deletions: yes, 58.3% vs. no, 87.0%, P = 0.02; CRLF2 expression: high, 55.6% vs. low, 85.3%, P = 0.04) but not in patients with ALL in the NCI-standard risk group (SR-ALL; IKZF1 deletions: yes, 80.0% vs. no, 84.4%, P = 0.75; CRLF2 expression: high, 83.3% vs. low, 89.2%, P = 0.77). Coexistence of IKZF1 deletions and CRLF2-high expression associated with poor outcomes. CONCLUSIONS: IKZF1 deletions and CRLF2-high expression predicted poor outcomes in patients with HR-ALL but not in patients with SR-ALL in our Japanese cohort.

Prophylactic post-transplant dasatinib administration in a pediatric patient with Philadelphia chromosome-positive acute lymphoblastic leukemia.

Philadelphia chromosome-positive acute lymphoblastic leukemia has a poor prognosis, even in pediatric patients. Although imatinib-containing chemotherapy can reportedly improve early event-free survival, allogeneic hematopoietic stem cell transplantation is still considered to be the main curative treatment option. Dasatinib, a novel abl tyrosine kinase inhibitor, is being used for the treatment of relapsed or refractory Philadelphia chromosome-positive acute lymphoblastic leukemia and is reported to have excellent efficacy. We used dasatinib after bone marrow transplantation prior to the anticipated relapse for the purpose of prophylaxis against relapse. After discontinuation of dasatinib administration, molecular remission has lasted for 7 months. Although preventive use of dasatinib is as yet uncommon, we consider that dasatinib may eradicate the minimal residual disease and prevent recurrence, and it is feasible to administer and appears to be safe. Further studies are needed to confirm our experience in this case.

Matched sibling donor stem cell transplantation for Fanconi anemia patients with T-cell somatic mosaicism.

SCT from HLA-identical sibling donors is generally associated with an excellent survival in FA patients if performed prior to the development of MDS or leukemia. However, the optimal conditioning regimen has not been defined. We report here our experience with 15 Japanese FA patients who underwent HLA-matched sibling donor SCT. The aim of this study is to compare radiation-based conditioning to Flu-based conditioning for FA patients in a Japanese population where the T-cell somatic mosaicism is higher than in the Caucasian population. Eight patients (a-group) received a radiation-based conditioning (500-600 cGy of thoracoabdominal/TBI) with CY dose modification (20-120 mg/kg), and ATG; two patients exhibited rejection. Seven patients (b-group) received CY (40 mg/kg), 150-180 mg/m(2) of Flu, and ATG. Durable engraftment was demonstrated in all patients. In FA patients, Flu-based conditioning may allow stable engraftment in matched sibling donor transplantation without radiation, even in patients with T-cell somatic mosaicism.

Job discrimination against childhood cancer survivors in Japan: a cross-sectional survey.

BACKGROUND: The aim of this study was to investigate the policies to identify job discrimination by company recruiters against childhood cancer survivors in Japan. METHODS: We conducted a cross-sectional study using a mailed questionnaire for the Japanese companies that were divided into three groups: companies listed on the stock market, companies not listed on the stock market, and public offices. We randomly selected 2000 of the 4000 listed companies and 2500 of the 4300 unlisted companies. We selected 47 public offices from prefectures and 17 from government ordinance-designated cities. Outcomes were health certificate requirements, how to treat past medical history and present illness, childhood cancer survivors' employment experience, and company's policy for evaluating applicants based on past medical history and present illness. RESULTS: Response rates were 17.7% for listed companies, 28.9% for unlisted companies, and 56.3% for public offices. A health certificate was required by 86% of listed companies, 77% of unlisted companies, and 75% of public offices. However, 33% of listed companies and 36% of unlisted companies, and none of the public offices demanded it at the time of application. Small numbers of private companies (0.7% of listed companies and 1.0% of unlisted companies) and public offices (4%) reject applicants outright if they have a disease in their past medical history. Using multivariate analysis, we found that large companies and company policies were significantly associated with the demand for a health certificate at the time of job applications. CONCLUSIONS: In Japan, employment-related discrimination still occurs in a small number of companies and public offices.

Assessment of late cardiotoxicity of pirarubicin (THP) in children with acute lymphoblastic leukemia.

BACKGROUND: Pirarubicin (tetrahydropyranyl-adriamycin: THP) is a derivative of doxorubicin with reportedly less cardiotoxicity in adults. However no studies of cardiotoxicity in children treated with THP have been reported. This study was performed to assess the THP-induced cardiotoxicity for children with acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: This study comprised 61 asymptomatic patients aged from 7.6 to 25.7 years old. Median follow-up time after completion of anthracycline treatment was 8.1 years (range: 1.7-12.5). The cumulative dose of THP ranged from 120 to 740 mg/m(2) with a median of 180 mg/m(2) . Patients underwent electrocardiogram (ECG), echocardiography, the 6-min walk test (6MWT), and measurements of serum brain natriuretic peptide (BNP) before and after exercise. RESULTS: All subjects showed normal left ventricular function assessed by echocardiography. Ventricular premature contraction in Holter ECG and reduced exercise tolerance in the 6MWT were detected in 2/46 (3.3%) and 5/41(12.2%), respectively. Abnormal BNP levels were detected in 6/60 (10%) both before and after exercise. The cumulative dose of THP was significantly correlated with BNP levels after exercise (r = 0.27, P = 0.03), but not with any other cardiac measurements. Further analysis revealed that subjects with a high cumulative dose ≧300 mg/m(2) had significantly higher BNP levels after exercise compared with subjects with a low cumulative dose <300 mg/m(2) (P = 0.04). CONCLUSIONS: No significant cardiac dysfunction was detected in long-term survivors who received THP treatment. The use of post-exercise BNP level to indicate high cardiotoxicity risk should be verified by further study.

Validation of the Japanese version of the Pediatric Quality of Life Inventory (PedsQL) Cancer Module.

BACKGROUND: The PedsQL 3.0 Cancer Module is a widely used instrument to measure pediatric cancer specific health-related quality of life (HRQOL) for children aged 2 to 18 years. We developed the Japanese version of the PedsQL Cancer Module and investigated its reliability and validity among Japanese children and their parents. METHODS: Participants were 212 children with cancer and 253 of their parents. Reliability was determined by internal consistency using Cronbach's coefficient alpha and test-retest reliability using intra-class correlation coefficient (ICC). Validity was assessed through factor validity, convergent and discriminant validity, concurrent validity, and clinical validity. Factor validity was examined by exploratory factor analysis. Convergent and discriminant validity were examined by multitrait scaling analysis. Concurrent validity was assessed using Spearman's correlation coefficients between the Cancer Module and Generic Core Scales, and the comparison of the scores of child self-reports with those of other self-rating depression scales for children. Clinical validity was assessed by comparing the on- and off- treatment scores using Kruskal-Wallis and Mann-Whitney U tests. RESULTS: Cronbach's coefficient alpha was over 0.70 for the total scale and over 0.60 for each subscale by age except for the 'pain and hurt' subscale for children aged 5 to 7 years. For test-retest reliability, the ICC exceeded 0.70 for the total scale for each age. Exploratory factor analysis demonstrated sufficient factorial validity. Multitrait scaling analysis showed high success rates. Strong correlations were found between the reports by children and their parents, and the scores of the Cancer Module and the Generic Core Scales except for 'treatment anxiety' subscales for child reports. The Depression Self-Rating Scale for Children (DSRS-C) scores were significantly correlated with emotional domains and the total score of the cancer module. Children who had been off treatment over 12 months demonstrated significantly higher scores than those on treatment. CONCLUSIONS: The results demonstrate the reliability and validity of the Japanese version of the PedsQL Cancer Module among Japanese children.

Medical visits of childhood cancer survivors in Japan: a cross-sectional survey.

BACKGROUND: Although more children with cancer continue to be cured, these survivors experience various late effects. Details of the medical visit behaviors of childhood cancer survivors (CCS) in adulthood remain to be elucidated. METHODS: In order to examine medical visits in the past and future of CCS, we performed a cross-sectional survey with self-rating questionnaires on medical visits of CCS compared with control groups (their siblings and the general population). RESULTS: Questionnaires were completed by 185 CCS, 72 of their siblings and 1000 subjects from the general population and the results were analyzed. Mean ages at this survey and the duration after therapy completions of CCS were 23 and 12 years, respectively. We found that the previous treatment hospitals (where CCS were treated for their cancer) were the most commonly visited medical facilities for the CCS group (74% for female patients and 64% for male patients) and more than half of the CCS preferred to continue visiting the previous treatment hospital with enough satisfaction in Japan. The multivariate analysis showed that female sex and relapse were significantly associated with the past visits to the previous treatment hospital and that the CCS with brain tumors or bone/soft tissue sarcomas and CCS with any late effects tended to continue the relationships with the hospital. In addition female sex was also significantly associated with desired future visits to the previous treatment hospital. On the other hand, the married CCS tended to be disinclined to visit the hospital it in the future. CONCLUSIONS: In order to optimize risk-based care and promote health for CCS after adulthood, we should discuss the medical transition with CCS and their parents.

Minimal residual disease-based augmented therapy in childhood acute lymphoblastic leukemia: a report from the Japanese Childhood Cancer and Leukemia Study Group.

BACKGROUND: The majority of minimal residual disease (MRD)-positive patients with acute lymphoblastic leukemia (ALL) have poor outcomes. The ALL2000 study was performed to evaluate the efficacy of augmented chemotherapy based on MRD-restratification in childhood ALL. PROCEDURE: Between 2000 and 2004, 305 eligible patients with precursor B or T-cell ALL were enrolled in the ALL2000 study. The ALL941-based therapy protocol utilized PCR MRD assays using Immunoglobulin and T-cell receptor gene rearrangements. They were initially stratified into three risk-groups according to leukocyte count and age, and MRD levels were measured at weeks 5 (TP1) and 12 (TP2) for a second stratification. From week 14, patients with MRD levels ≥ 10(-3) received an increase in therapy (one risk group higher), while the remainder continued to receive the initial risk-adapted therapy. RESULTS: The overall 5-year event-free survival (EFS) rate for ALL2000 was 79.7 ± 2.4%. MRD stratification was feasible for 234 of 301 patients (77%) who achieved complete remission. The EFS rate of the MRD stratifiable (MRD) group was 82.5 ± 2.6%, considerably superior to the 74.7 ± 5.7% of MRD non-stratifiable (Non-MRD) group (P = 0.084) and the 74.4 ± 2.1% for ALL 941 (P = 0.012). MRD-positive patients at TP2 showed inferior outcomes as compared with MRD-negative cases, but the difference did not reach a statistically significant level in any risk groups or immunophenotypes. CONCLUSIONS: These results suggest that augmented therapy for MRD-positive patients at TP2 contributed to better outcomes of the ALL2000 study.

[Effectiveness of remission induction with high-dose cytarabine for relapsed or refractory pediatric acute leukemia].

We conducted a multicenter postmarketing study to investigate the efficacy and safety of reinduction therapy with a high-dose cytarabine-containing regimen for pediatric patients with relapsed or refractory acute leukemia. Seven of 13 patients (53.8%) with ALL achieved complete or partial remission, and only 1 of 6 patients (16.7%) with AML achieved partial remission. The frequent non-hematologic adverse events were gastrointestinal toxicities, such as vomiting, diarrhea and abdominal pain, as well as pyrexia and headache. Infection appeared in 9 of 20 (45%) patients. There were two death during reinduction therapy. One died of invasive bronchopulmonary aspergillosis, and the other died of intracranial hemorrhage and renal failure. These results indicated that a high-dose cytarabine regimen is effective as reinduction therapy in pediatric patients with relapsed ALL, and supportive care is essential to prevent or control treatment-related adverse events, such as infection.

Clinical impact of HLA-DR15, a minor population of paroxysmal nocturnal haemoglobinuria-type cells, and an aplastic anaemia-associated autoantibody in children with acquired aplastic anaemia.

Aplastic anaemia (AA) is defined as a pancytopenia caused by bone marrow failure, and its pathogenesis is thought to involve autoimmune processes. Several predictive markers of the response to immunosuppressive therapy (IST) have been proposed, which appear to reflect the immune pathophysiology. We prospectively investigated the presence of human leucocyte antigen (HLA)-DR15, a minor population of paroxysmal nocturnal haemoglobinuria (PNH)-type cells, and antibodies to the recently identified autoantigen postmeiotic segregation increased 1 (PMS1) in 103 children with AA enrolled in a multicentre study. In contrast to adults, children with AA did not show an increased frequency of HLA-DR15. In addition, a sensitive flow cytometric assay revealed that children with AA have a much lower prevalence of PNH-type cells (21.4%) than reported for adults with this disease. An immunoblotting assay detected anti-PMS1 antibody in 15 of 103 (14.6%) of the children. Finally, the response rate to IST was not significantly different between patients with and without DR15 (45.5% vs. 54.0%), PNH-type cells (68.2% vs. 53.1%) or anti-PMS1 antibody (40.0% vs. 59.1%). The current study did not confirm a correlation between these markers and the response to IST, suggesting that there is a difference in the pathophysiologies of adult and paediatric AA.

Transcriptional profiling in hepatoblastomas using high-density oligonucleotide DNA array.

Hepatoblastoma is a common hepatic tumor in children. Although evidence regarding cytogenetic and molecular genetic alterations in hepatoblastomas has been reported, the molecular events affecting the biologic characteristics of this tumor, including alterations of the gene expression profile, are largely unknown. To identify genes differentially expressed between nondiseased liver (NDL) and hepatoblastoma tumor (HBT), we analyzed the gene expression profile in 14 NDL and 16 HBT samples using a high-density oligonucleotide DNA array. Using Mann-Whitney U test followed by the k-nearest neighbor algorithm, we identified 26 genes (predictor genes) that were able to assign unknown samples derived from NDL and HBT to either the NDL group or HBT group with 100% accuracy. Using a cross-validation approach, we confirmed that the k-nearest neighbor algorithm assigned the particular samples derived from NDL and HBT to either the NDL or HBT group with 93.3% (28/30 samples) accuracy. In the 26 predictor genes, we found alteration of the expression of genes regulating cell division (NAP1L1, STMN1, CCNG2, and CDC7L1) and tumor cell growth (IGF2 and IGFBP4) in HBT. Four predictor genes (ETV3, TPR, CD34, and NR1I3) were also found to be mapped to the chromosomal region 1q21 approximately q32, which has been reported to be frequently involved in the development of hepatoblastoma. The findings obtained in this study suggest that alteration of the expression of some genes regulating cell division and tumor cell growth may be characteristics of the gene expression profile in HBT, and that alteration of the expression of the four predictor genes mapped to chromosomal region 1q21 approximately q32 may also contribute to the differences in gene expression profile between NDL and HBT.