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Biomedical subjects

R Hanada

Publications and source records attributed to R Hanada.

At least 55 records · Page 3Linked to original sources
PubMed1998

The p16 (CDKN2A) gene is involved in the growth of neuroblastoma cells and its expression is associated with prognosis of neuroblastoma patients.

We previously reported that loss of heterozygosity (LOH) on chromosome 9p21 correlates with poor prognosis of neuroblastoma and the p16 gene is not expressed in approximately two thirds of neuroblastoma cell lines. Here we demonstrated that p16 expression was induced by 5-aza-2-deoxycytidine treatment in cell lines with 5' CpG island methylation but not in cell lines without methylation. Furthermore, the cell cycle of neuroblastoma cell lines significantly delayed with accumulation of cells in G1 phase by transfection of a wild-type p16 expression vector. These results indicate that p16 is inactivated in part by DNA methylation and its expression is involved in the growth of neuroblastoma cells in vitro. To assess the biological and clinical significance of p16 expression in primary tumors, we undertook immunohistochemical analysis in 74 paraffin sections of neuroblastomas. p16 protein was undetectable in 45 of 74 cases (61%) and lack of p16 expression significantly correlated with poor prognosis of patients and advanced stage of the disease. There was no correlation between loss of p16 expression and N-myc amplification in these tumors. These results indicate that inactivation of the p16 gene is involved in the progression of neuroblastoma independently of N-myc amplification.

Azacitidine↗
PubMed1998

ABI-1, a human homolog to mouse Abl-interactor 1, fuses the MLL gene in acute myeloid leukemia with t(10;11)(p11.2;q23).

Recurrent translocation t(10;11) has been reported to be associated with acute myeloid leukemia (AML). Recently, two types of chimeric transcripts, MLL-AF10 in t(10;11)(p12;q23) and CALM-AF10 in t(10;11)(p13;q14), were isolated. t(10;11) is strongly associated with complex translocations, including invins(10;11) and inv(11)t(10;11), because the direction of transcription of AF10 is telomere to centromere. We analyzed a patient of AML with t(10;11)(p11.2;q23) and identified ABI-1 on chromosome 10p11.2, a human homolog to mouse Abl-interactor 1 (Abi-1), fused with MLL. Whereas the ABI-1 gene bears no homology with the partner genes of MLL previously described, the ABI-1 protein exhibits sequence similarity to protein of homeotic genes, contains several polyproline stretches, and includes a src homology 3 (SH3) domain at the C-terminus that is required for binding to Abl proteins in mouse Abi-1 protein. Recently, e3B1, an eps8 SH3 binding protein 1, was also isolated as a human homolog to mouse Abi-1. Three types of transcripts of ABI-1 gene were expressed in normal peripheral blood. Although e3B1 was considered to be a full-length ABI-1, the MLL-ABI-1 fusion transcript in this patient was formed by an alternatively spliced ABI-1. Others have shown that mouse Abi-1 suppresses v-ABL transforming activity and that e3B1, full-length ABI-1, regulates cell growth. In-frame MLL-ABI-1 fusion transcripts combine the MLL AT-hook motifs and DNA methyltransferase homology region with the homeodomain homologous region, polyproline stretches, and SH3 domain of alternatively spliced transcript of ABI-1. Our results suggest that the ABI-1 gene plays a role in leukemogenesis by translocating to MLL.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Congenital mediastinal dumbbell neuroblastoma with spontaneous regression of liver metastases.

We report a patient with a congenital mediastinal dumbbell neuroblastoma (NB) presenting as respiratory distress at birth rather than a neurologic deficit. The tumor did not respond to low-dose chemotherapy, but radiotherapy and surgery were effective. The patient was observed postoperatively without further therapeutic intervention considering the favorable biologic factors despite the appearance of liver metastases, which ultimately regressed spontaneously. The authors believe that most congenital NBs have favorable outcomes with a possibility of spontaneous regression, and that an understanding of the biologic features of tumors is important to avoid overtreatment of lesions with a favorable prognosis. Keywords Congenital neuroblastoma. Dumbbell tumor. Liver metastasis. Spontaneous regression

Combined Modality Therapy↗
PubMed1998

Spontaneous regression of localized neuroblastoma detected by mass screening.

PURPOSE: To clarify whether and when neuroblastomas identified through screening do regress, and to ascertain how to treat them appropriately, we observed screened patients who had localized tumors, without any therapeutic intervention. PATIENTS AND METHODS: The criteria for the observation program were as follows: disease stage I or II; tumor less than 5 cm in diameter; no invasion to the intraspinal canal or growth to the great vessels; urinary vanillylmandelic acid (VMA) and homovanillic acid (HVA) less than 50 microg/mg creatinine; and informed consent. Of 25 patients identified through screening for 6-month-old infants in Saitama Prefecture, Japan between April 1994 and March 1996, 11 patients who met the criteria and one other patient with stage III tumor were enrolled onto the program. They were examined by abdominal ultrasonography (US) and their urinary VMA and HVA levels were assessed approximately once per month. The observation periods ranged from 4 to 27 months. RESULTS: The 11 tumors decreased in size, although one of these 11 tumors initially enlarged until the patient was 12 months of age and decreased in size thereafter. One other tumor slightly increased in size. Urinary VMA levels decreased in all patients. None of the tumors had completely disappeared by the last observation day. CONCLUSION: Our results suggest that regression of screened neuroblastoma is not a rare phenomenon. At present, it seems reasonable to adopt a wait-and-see strategy, with careful observation, for selected stage I or II tumors identified in infants screened at 6 months of age.

Homovanillic Acid↗
PubMed1998

[TAL1 gene analysis in T-cell malignancies].

Site-specific recombination of the TAL1 gene was analyzed by Southern blotting and polymerase chain reaction (PCR) in 44 cases of childhood T-cell acute lymphoblastic leukemia (T-ALL), 20 cases of childhood T-cell non-Hodgkin's lymphoma (T-NHL) and 35 cases of adult T-cell malignancies. This recombination was found in 10 (22.7%) of 44 childhood T-ALL patients, but in none of the T-NHL or adult T-cell malignancies. Recombination of the TAL1 gene was therefore suggested to be specific for childhood T-ALL. The immunophenotypic features of the 10 T-ALL patients with this recombination were CD1-, CD2+, CD4-, CD7+, CD10-, and they had a significantly better outcome than other T-ALL cases without the recombination. The PCR technique revealed minimal residual disease (MRD) in 2 patients. One showed persistent MRD, while in the other MRD was recognized only at initial diagnosis. Further investigation is needed whether T-ALL with this recombination constitutes a distinct clinical subgroup among childhood T-ALL patients.

Adolescent↗
PubMed1997

Expression and mutational analysis of the DCC, DPC4, and MADR2/JV18-1 genes in neuroblastoma.

Loss of heterozygosity (LOH) on chromosome 18q21 is found frequently in various human cancers. Three candidate tumor suppressor genes, DCC (deleted in colorectal carcinomas), DPC4 (deleted in pancreatic carcinomas, locus 4), and MADR2/JV18-1 (MAD-related gene 2), have been cloned and identified from this chromosome region. We have reported recently that LOH on chromosome 18q is observed frequently in neuroblastoma. Alterations of DCC are involved in many human tumors. DPC4 and MADR2/JV18-1 are recently demonstrated to be altered in pancreatic and colorectal cancers, respectively. To confirm if inactivation of the DCC, DPC4, and MADR2/JV18-1 genes is involved in the pathogenesis of neuroblastoma and to clarify the mechanism of inactivation, we analyzed the expression of DCC, DPC4, and MADR2/JV18-1 in neuroblastoma cell lines and primary tumors by reverse transcription-PCR and investigated the mutations in the coding regions of these genes by PCR/reverse transcription-PCR single-strand conformation polymorphism. We found that 12 of 25 (48%) cell lines and 14 of 32 (44%) primary tumors, including 3 with 18q LOH, had absent or reduced expression of DCC mRNA. Expression was more likely to be reduced in advanced (67%) than in early stage neuroblastomas (24%) (P = 0.036), suggesting that inactivation of the DCC gene plays an important role in the progression of neuroblastoma. Altered expression of DPC4 was found in six (24%) cell lines and six (19%) tumors. MADR2/JV18-1 expression was reduced or absent only in four (16%) cell lines and three (9%) tumors. Mutations of the DCC genes were examined in 25 of 29 exons in neuroblastoma cell lines, and those exons in which mutations were found were further examined in primary tumors. We found missense mutations of AAC (Asn) to AGC (Ser) at DCC codon 176 in one cell line and ACC (Thr) to ATC (Ile) at codon 1105 in one cell line and tumor, respectively; polymorphisms of CGA (Arg) to GGA (Gly) at codon 201 and TTT (Phe) to TTG (Leu) at codon 951 in most of the cell lines and tumors; and a silent mutation of GAG (Glu) to GAA (Glu) at codon 118 in four cell lines and five primary tumors. We did not identify any mutations in the DPC4 and MADR2/JV18-1 genes in neuroblastoma. Our results suggested that mutations of the DCC gene may be involved in the pathogenesis of neuroblastomas but failed to account for the relatively high frequency of the altered expression, implying that other mechanisms are responsible for the inactivation of the DCC gene in neuroblastoma. Low frequency of reduced or absent mRNA expression and lack of mutations in DPC4 and MADR2/JV18-1 genes suggested a limited role for these two genes in neuroblastoma.

Cell Adhesion Molecules↗
PubMed1997

In vitro drug sensitivity testing can predict induction failure and early relapse of childhood acute lymphoblastic leukemia.

It is vital to develop effective therapy for children with acute lymphoblastic leukemia (ALL), in whom no remission occurs or who suffer relapse with current protocols. Cellular drug resistance is thought to be an important cause of induction failure and relapse. We performed in vitro tests of bone marrow samples in 196 children with newly diagnosed ALL with a 4-day culture and a methyl-thiazol-tetrazolium assay. We tested 16 drugs and calculated the 70% lethal dose (LD70) for 14 drugs and the leukemic cell survival (LCS) rate for dexamethasone and prednisolone. For each single drug, patients were classified into two groups, sensitive or resistant, by median concentration of LD70 or LCS. When patients were classified into three groups by sensitivity to four drugs of DPAV (dexamethasone, prednisolone, L-asparaginase, and vincristine), 3-year event-free survival (EFS; 95% confidence intervals) of the super sensitive group (SS; sensitive to all 4 drugs) was 0.833 (0.690 to 0.976), that of the intermediate sensitive group (IS; sensitive to 2 or 3 drugs) was 0.735 (0.609 to 0.863), and that of the relatively resistant group (RR; sensitive to no drugs or to 1 drug) was 0.541 (0.411 to 0.670; P = .0008). We then investigated the relationship between the above four-drug sensitivity and the time of relapse. The SS and IS patients tended to maintain continuous complete remission, and RR patients tended to undergo induction failure and early and late relapse (P = .004). Initial white blood cell count, immunologic classification, and age were also predictive factors, but the patient numbers showed no statistical correlation between these factors and the four-drug sensitivity groups (SS, IS, and RR). When we took three groups SS/IS/RR and investigated the EFS for various clinical groups, DPAV sensitivity strongly influenced EFS in the standard-risk ALL (P = .016). In vitro drug sensitivity testing provides additional prognostic information about childhood ALL, and early detection of drug resistance at the time chemotherapy commences may provide a successful strategy for individualizing treatment, as the results indicate de novo resistance to front-line drugs and suggest alternative, second-line drugs.

Aclarubicin↗
PubMed1997

Deletion map of chromosome 9 and p16 (CDKN2A) gene alterations in neuroblastoma.

We reported previously that loss of heterozygosity (LOH) on chromosomes 2q, 9p and 18q frequently occurs in neuroblastoma and that patients with 9p LOH in the tumors showed statistically significant association with an advanced stage of the disease and poor prognosis. To determine the role of chromosome 9 loss in neuroblastoma, we performed deletion mapping of chromosome 9 in 80 cases of neuroblastoma using 11 polymorphic microsatellite markers and a restriction fragment length porymorphism marker. LOH at one or more loci on chromosome 9 was detected in 33 of 80 cases (41%). Chromosome 9p was lost in 24 of 80 cases (32%), whereas chromosome 9q was lost in 18 of 80 cases (23%). There were two commonly deleted regions mapped to 9p21 between the D9S171 marker and the IFNB1 marker and 9q34-qter distal to the D9S176 marker. In addition, patients with LOH at 9p21 but not at 9q34-qter in the tumors showed statistically significant association with poor prognosis (P = 0.023). Because the commonly deleted regions at 9p21 includes the p16 (CDKN2A) gene, the status of the p16 gene was further examined in 80 fresh tumors and 19 cell lines of neuroblastoma. A missense mutation was detected at codon 52 in a fresh tumor. The p16 gene was not expressed in 13 of 19 cell lines (72%), and 5 of the 13 cell lines displayed methylation of the CpG island surrounding the first exon of the p16 gene. These results suggest that the p16 gene is a candidate tumor suppressor gene for neuroblastoma, and its inactivation may contribute to the progression of neuroblastoma.

Carrier Proteins↗
PubMed1997

Detection of chimeric mRNAs by reverse transcriptase-polymerase chain reaction for diagnosis and monitoring of acute leukemias with 11q23 abnormalities.

Recurrent translocations involving chromosome band 11q23 are often found in human acute leukemias. Recently, the MLL gene on 11q23 and 10 partner genes involved in these translocations have been cloned and characterized. We performed a reverse transcriptase-polymerase chain reaction (RT-PCR) to detect the resultant der(11) chimeric mRNAs of the 3 types of 11q23 translocations including t(4;11), t(9;11), or t(11;19), in 14 leukemia patients with MLL gene rearrangements. At diagnosis or relapse, chimeric mRNA could be detected in all of the 4 patients with t(4;11), 2 of 3 with t(9;11), 2 of 3 with t(11;19), and 1 of 4 with unsuccessful karyotype. In 5 patients, we could monitor minimal residual disease (MRD) serially through the clinical course. One patient, in whom chi-meric mRNA was detected during complete remission (CR) just after the induction chemotherapy, relapsed within 2 months and died, while 2 patients in which chimeric mRNA was not detected remained in CR from 10-23 months. These findings suggest that RT-PCR is a useful approach for detecting which partner gene is involved in the translocation and monitoring MRD in patients with MLL gene rearrangement. Nonetheless, the clinical relevance of MRD evaluation by RT-PCR monitoring remains controversial. Long-term and prospective investigation of a larger series of patients is needed to confirm the clinical significance of monitoring MRD by RT-PCR method.

Acute Disease↗
PubMed1997

Spontaneous remission of chronic hepatitis C in children.

UNLABELLED: The clinical course of 48 children with chronic hepatitis C (33 boys, 15 girls; mean age: 12.2 years) was monitored for more than 3 years to clarify its natural course. All patients were positive for the second-generation antibody to hepatitis C virus (anti-HCV) and for serum hepatitis C virus (HCV) RNA. All but one patient had a history of blood transfusion. Serum levels of alanine aminotransferase (ALT) had been abnormal for more than 1.5 years. Spontaneous remission defined as a biochemical remission lasting more than 1 year in association with the disappearance of serum HCV RNA, occurred in 4 (8.3%), however, in 25%, HCV RNA was still detectable in the liver even after its disappearance from serum. In this patient, the level of antibody to HCV core antigen (anti-HCV core) did not decrease significantly and serum HCV RNA eventually reappeared. The serum titre of HCV RNA in the 4 children with spontaneous remission was lower than in the remaining 44 children. Spontaneous remission may occur in children with chronic hepatitis C in whom the serum titre of HCV RNA is low and serum level of anti-HCV core decreases significantly. Assessment of the intrahepatic HCV RNA is necessary to confirm complete remission. CONCLUSION: A low serum titre of HCV RNA and a significant decrease in the serum titre of anti-HCV core were associated with spontaneous remission in children with chronic hepatitis C. Intrahepatic HCV RNA assessment is necessary to confirm complete remission.

Adolescent↗
PubMed1997

Mutations of the RAS genes in childhood acute myeloid leukemia, myelodysplastic syndrome and juvenile chronic myelocytic leukemia.

Using the polymerase chain reaction-single strand conformation polymorphism method and direct sequencing, 12 acute myeloid leukemia (AML) cell lines and 108 fresh childhood myeloid tumor specimens, including 67 AML, 29 myelodysplastic syndrome (MDS), and 12 juvenile chronic myelocytic leukemia (JCML) were examined for mutation in H-, K-, and N-RAS genes. The mutation was found in eight of the 120 samples (6.7%), which consisted of four cell lines (33.3%) and four fresh myeloid tumors (3.7%). The frequency of the mutation in the cell lines was apparently higher than that in fresh myeloid tumors. K-RAS gene mutations were found in two of the 67 fresh AML specimens (3%). Interestingly, these two patients had 11q23 translocations. The N-RAS gene mutation was found in one of the 29 specimens (3.4%) of MDS and in one of the 12 specimens (8.3%) of JCML. All mutations were found in codon 12, 13 or 61 of the N-RAS and K-RAS genes. Frequency of mutation of RAS genes in fresh myeloid malignancies was very low. These findings suggest that mutation of RAS genes does not play an important role in the development of childhood myeloid malignancies.

Acute Disease↗
PubMed1997

Alterations of the tumour suppressor gene DCC in neuroblastoma.

The deleted in colorectal carcinoma (DCC) gene, a candidate tumour suppressor, might be inactivated in a number of human cancers. In order to evaluate the possible role of DCC alterations in the pathogenesis of neuroblastoma, we examined 25 neuroblastoma cell lines and 16 primary tumours, including 6 samples with loss of heterozygosity (LOH) at the DCC locus for DCC mRNA expression, by using the reverse transcriptase-polymerase chain reaction (RT-PCR) technique. The level of DCC expression was significantly reduced or undetectable in 12 of 25 (48%) cell lines and 7 of 16 (44%) primary tumours, suggesting that inactivation of the DCC gene is involved in the development of neuroblastoma. Three of the 6 tumours with LOH at the DCC locus revealed reduced DCC mRNA expression, indicating that LOH at the DCC locus might have affected the levels of DCC mRNA. We also screened for mutations in 4 exons of the DCC gene in 12 cell lines by using PCR-single strand conformation polymorphism (PCR-SSCP) analysis. Point mutations were not found except a polymorphic change at codon 201. The mechanism for inactivation of the DCC gene will be further investigated.

Genes, DCC↗
PubMed1997

Alterations of p16 and p15 genes in acute leukemia with MLL gene rearrangements and their correlation with clinical features.

p16 and p15 genes are putative tumor suppressor genes located on chromosome 9p21. In acute leukemias, alterations of p16 and p15 genes have been reported to occur exclusively in lymphoid lineage. We analyzed alterations of p16 and p15 genes in 46 acute leukemias with MLL gene rearrangements by Southern blot analysis, and investigated the association with clinical characteristics. We identified homozygous deletion of p16 and p15 genes in five (19%) of 27 acute lymphoblastic leukemias (ALLs) and in two (11%) of 19 acute myeloid leukemias (AMLs). Patients with homozygous deletion of p16 and p15 genes showed higher average leukocyte counts (343 x 10(9)/l vs 271 x 10(9)/l) and lower estimated 2-year survival rates than those with normal p16 and p15 genes (14.3 vs 30.7%), although the differences were not statistically significant. In addition, we investigated mutation of p16 gene by polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) in 31 patients, but no mutation was found in the patients tested. Our results suggest that alterations of p16 and p15 genes are involved in a subset of acute leukemias with MLL gene rearrangement not only of lymphoid but also of myeloid phenotype. Homozygous deletion of p16 and p15 genes may be a possible adverse prognostic factor, although further analysis would be needed to confirm it.

Adolescent↗
PubMed1997

[Alterations of the p53 gene and clinical features in childhood acute lymphoblastic leukemia].

Correlations between alterations of the p53 gene and clinical features were examined in childhood acute lymphoblastic leukemia (ALL). We analyzed 147 patients and 38 cell lines for p53 mutations within exons 5 to 9 (2 to 11 in some of them) by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis and direct sequencing. p53 gene mutations were found in 3 of 62 (5%) patients at diagnosis, 1 of 14 (7%) patients at relapse, and 13 of 20 (65%) cell lines in T-ALL, 2 of 20 (10%) patients at diagnosis, 4 of 4 (100%) patients at relapse, and 4 of 5 (80%) cell lines in t(1;19)-ALL, 1 of 23 (4%) patients at diagnosis, 2 of 22 (9%) patients at relapse, and 5 of 12 (42%) cell lines in common ALL other than t(1;19) or t(9;22)-ALL and 3 of 3 (100%) patients at diagnosis in B-ALL. In t(1;19)-ALL, p53 gene alterations were associated with a poor prognosis. The patients with p53 mutations had a trend towards poor prognosis in childhood ALL without B-ALL. p53 gene mutation is not always associated with the current prognostic factors. This alteration may become one of the important prognostic factors, if the detection of a small number of the leukemic cells with the p53 gene mutation would be possible.

Adolescent↗
PubMed1996

Fusion of the MLL gene with two different genes, AF-6 and AF-5alpha, by a complex translocation involving chromosomes 5, 6, 8 and 11 in infant leukemia.

We analysed a complex translocation involving chromosomes 5, 6, 8 and 11 in a case of infant leukemia. Molecular analysis of the MLL gene revealed that MLL was fused with two different genes, AF-6 on chromosome 6q27 and AF-5alpha. AF-5alpha, the 11th partner gene fused with MLL, is a novel gene mapped to chromosome 5q12, which encodes a 31 kDa protein of 269 amino acids and contains a possible nuclear targeting sequence, a potential leucine zipper dimerization motif and an alpha-helical coiled-coil domain. In situ hybridization and molecular cloning analyses demonstrated that two different types of chromosomal recombination had occurred in the cells. One was a three-way translocation among chromosomes 6, 8 and 11, and the other was an insertion of a chromosome 5-derived segment into the breakpoint of chromosomes 8 and 11. Accordingly, the karyotype was defined as del(5)(q11.2q12), der(6)t(6;8) (q27;q11.2), der(8)(8pter-->8q11.2::5q11.2-->5q12::11q23-->++ +11qter), der(11)t(6;11) (q27;q23). Thus, the MLL gene created two different fusion mRNAs, since the chromosome 11 split into two different chromosomes 5 and 6. This is the first report demonstrating fusion of the MLL gene with two different genes by a complex translocation.

Base Sequence↗
PubMed1996

Efficacy of interferon in treating chronic hepatitis C in children with a history of acute leukemia.

Interferon (IFN) is effective in treating adults as well as children with chronic hepatitis C. We investigated the efficacy of IFN therapy in 13 children with underlying acute leukemia who had chronic hepatitis C (age range, 5 to 17 years; mean age, 9.9 years). Natural IFN- alpha was administered at a dose of 0.1 mega unit (MU)/kg (maximum dose, 6.0 MU) daily for 2 weeks and then three times per week for an additional 22 weeks (total dose, 8 MU/kg). IFN treatment was initiated at least 2 years after the completion of treatment for acute leukemia. A complete response was obtained in 5 children (38%). The serum level of anti-hepatitis C virus core antibody was closely related to the response to IFN. IFN therapy was well tolerated by all but 1 of the children, who developed mild transient heart failure 4 months after the initiation of therapy. IFN therapy for children with chronic hepatitis C who had underlying acute leukemia was beneficial. However, further trials are required to confirm the safety and improve the dosage schedule of IFN therapy.

Acute Disease↗