Shigeru Ohta

Aberrations of the hSNF5/INI1 gene are restricted to malignant rhabdoid tumors or atypical teratoid/rhabdoid tumors in pediatric solid tumors

The hSNF5/INI1 gene, which encodes a subunit of the SWI/SNF family of chromatin‐remodeling complexes and is located at 22q11.2, has been reported as a tumor suppressor gene inactivated in malignant rhabdoid tumors (MRTs). We analyzed this gene in varieties of pediatric solid tumors including MRTs, using the reverse transcription‐polymerase chain reaction (PCR) and PCR‐single strand conformation polymorphism method. We found 5 homozygous deletions, 2 truncated mutations, one missense mutation, and one silent mutation of the hSNF5/INI1 gene in 7 MRT cell lines, and one homozygous deletion, one microdeletion, one splicing acceptor site mutation, and one absence of expression in 7 fresh tumor tissues of MRT and atypical teratoid (AT)/rhabdoid tumors (RTs). Homozygous deletions were also found in one (KYM‐1) of 8 rhabdomyosarcoma (RMS) cell lines. To investigate characteristics of the KYM‐1 cell line, we have established KYM‐1 tumors in nude mice into which KYM‐1 cells were transplanted. Notably, we found that MyoD1, known as a marker for RMS, was not expressed in the KYM‐1 cell line as well as MRT cell lines and fresh tumors. Histopathologic, cytogenetic, and molecular studies of the KYM‐1 cell line and KYM‐1 tumors in nude mice have revealed that this RMS cell line should be MRT rather than RMS. RMS‐carrying aberrations of the hSNF5/INI1 gene should be reevaluated. No aberrations of this gene were found in the other 34 cell lines or 80 fresh tumor specimens except the single nucleotide polymorphisms in the 3′ noncoding region. These results suggest that alterations of the hSNF5/INI1 gene were restricted to MRTs or AT/RTs in pediatric solid tumors.

Marginal Decrease in Mortality and Marked Increase in Incidence as a Result of Neuroblastoma Screening at 6 Months of Age: Cohort Study in Seven Prefectures in Japan

PURPOSE To determine the usefulness of 6-month screening for neuroblastoma. PATIENTS AND METHODS The cumulative incidence rates (IRs) and cumulative mortality rates (MRs) of neuroblastoma in children younger than 60 months of age were analyzed for control (n = 713,025), qualitative screening (Qual Screen, n = 1,142,519), and quantitative screening (Quan Screen, n = 550,331) cohorts, and for Screened and Unscreened subgroups within screening cohorts. RESULTS IRs (per 100,000) for infants aged 6 to 11 months were 1.12 in Control, 5.69 in Qual Screen (P <.0001), and 17.81 in Quan Screen (P <.0001); IRs for children aged 12 to 59 months were 7.29 in Control, 5.86 in Qual Screen (P =.28), and 6.36 in Quan Screen (P =.60). IRs for children aged 12 to 59 months in Unscreened or Screened subgroups remained at the same level. When patients diagnosed at younger than 6 months of age were excluded, the MR (per 100,000) under 60 months for Control was 4.21; those in Unscreened and Screened subgroups were 3.84 and 2.53 in Qual Screen (P =.30), and 3.20 and 1.97 in Quan Screen (P =.73), respectively; MRs between Control and Unscreened subgroups revealed no significant differences (P =.89 in Qual Screen, P =.85 in Quan Screen). CONCLUSION Six-month screening resulted in a marked increase in incidence for infants with no significant decrease in incidence for children older than 1 year of age. A decrease in mortality was observed, but it was not significant. The usefulness of screening is questionable, because the decrease of mortality should be balanced against the adverse effect of overdiagnosis and the psychological burden on parents and children.

Highly aggressive behavior of malignant rhabdoid tumor: a special reference to SMARCB1/INI1 gene alterations using molecular genetic analysis including quantitative real-time PCR

PurposeSMARCB1/INI1, which negatively regulates cell cycle progression from G0/G1 into the S-phase via the p16INK4a-RB-E2F pathway, has been reported to be inactivated homozygously by deletion and/or mutations in malignant rhabdoid tumor (MRT). In the current study, we investigated the alteration of the SMARCB1/INI1 gene using simple methods, and its gene product at the protein level. Moreover, we investigated the status of hyperphosphorylation in RB protein, known as a key cell cycle molecule.MethodsThree cell lines and 11 formalin-fixed, paraffin-embedded specimens of MRT were investigated. SMARCB1/INI1 gene alteration was analyzed with simple methods as a quantitative real-time PCR and direct sequencing method. Furthermore, SMARCB1/INI1 and RB protein were immunohistochemically evaluated.ResultsIn 12 of 14 cases, we detected genetic alterations comprised of nine (including three cell lines) homozygous deletions and three mutations, which can induce abnormal expression of gene products. At the protein level, SMARCB1/INI1 immunohistochemical expressions were not detected in any cases. Twelve out of 14 cases showed high-level (+5) expression of tRB (both hyperphosphorylated and underphosphorylated RB), combined with low-level (+1) expression of uRB (underphosphorylated RB), indicating a high rate of hyperphosphorylation.ConclusionsWe could analyze the SMARCB1/INI1 gene alteration with simple methods, and SMARCB1/INI1 gene alteration was found in 12 of 14 cases. Especially, quantitative real-time PCR was a convenient and accurate method. In addition, a high rate of hyperphosphorylation of RB gene was recognized. These results suggest that the clinically aggressive character of MRT is caused by the inactivation of the SMARCB1/INI1 gene.

Prognostic factors of Epstein–Barr virus-associated hemophagocytic lymphohistiocytosis in children: Report of the Japan Histiocytosis Study Group

Despite several advances in the treatment of Epstein–Barr virus (EBV) in recent years, patients with Epstein–Barr virus‐associated hemophagocytic lymphohistiocytosis (EBV‐HLH) do not always show satisfactory outcomes. We here conducted a nationwide survey in Japan to identify prognostic factors of EBV‐HLH in children with this disease in an effort to improve the management and the outcomes of these patients.

Clinical characteristics and outcomes of chédiak–Higashi syndrome: A nationwide survey of Japan

Chédiak–Higashi syndrome (CHS) is a rare autosomal recessive disorder characterized by immunodeficiency, neurological dysfunction, and oculocutaneous albinism. Recently, several clinical CHS phenotypes have been reported. Here, we report results of a nationwide survey performed to clarify clinical characteristics and outcomes of CHS patients in Japan.

Destruction of external granular layer and subsequent cerebellar abnormalities.

SummaryThis study was undertaken to elucidate the relationship between the time of destruction of the external granular layer and subsequent cerebellar abnormalities. Mice were injected s. c. with 30 mg/kg body weight (b. wt.) of cytosine arabinoside on days 2, 3, and 4, on days, 4, 5, and 6, on days 7, 8, and 9, and on days 10, 11, and 12, and designated as group I, II, III, and IV, respectively.In group I, disarrangement of Purkinje cells and heterotopic granule cells in the molecular layer were observed on all lobes of cerebellum. Heterotopic granule cells were seen on all lobes in group II, whereas disarrangement of Purkinje cells was observed only in the region from the anterior to middle lobes. In group III, heterotopic granule cells were limited to the area from anterior to middle lobes, but there was no disarrangement of Purkinje cells. Group IV cerebellum did not show abnormal cytoarchitecture.Golgi-Cox studies showed abnormal arborization of Purkinje cells in each experimental group. They were arbitrarily classified into inverted Purkinje cells, lying Purkinje cells, T-shaped Purkinje cells, and poorly arborized Purkinje cells. The earlier the postnatal treatment the more severe were the abnormalities of Purkinje cell dendrite.According to the electron-microscopic study, some glomerular synaptic complexes, which are normally confined to the internal granular layer, were observed even in the molecular layer in groups I, II, and III. Some of the Purkinje cell dentritic spines did not make synapses with parallel fibers in any of the experimental groups.The results indicate that severity of abnormal arborization of Purkinje cells is dependent on the period of destruction of the external granular layer. Formation of heterotopic granule cells was dependent on the destruction of the external granular layer up to day 10 after birth.

MALIGNANT RHABDOID-TUMOR CELL LINE SHOWING NEURAL AND SMOOTH-MUSCLE-CELL PHENOTYPES

Malignant rhabdoid tumor (MRT) is a rare and extremely aggressive malignant tumor in childhood. In this study, an MRT cell line, designated KP‐MRT‐NS, was established from the ascitic fluid taken from an 11‐month‐old girl, whose tumor had originated from the left kidney. Ultrastructural findings demonstrated the typical aggregation of whorls of intermediate filaments. Chromosome constitution was described as 46, XX, add (10)(q26)[17]/46, idem, dis (1;2)(q22;q31)[3] based on ISCN (1995) and a del (22)(q11.2) was not found in this cell line. The origin of MRT is controversial, various cellular origins having been proposed because of the phenotypic diversity of MRT. Therefore, in this study, to clarify the origin of MRT, the expressions of cytoplasmic proteins including smooth‐muscle‐specific proteins (α‐smooth‐muscle actin, basic calponin, smooth‐muscle‐myosin‐heavy‐chain isoforms of SM1 and SM2) in the primary‐MRT tissue and cell line were analyzed. In the primary‐tumor tissue, the expressions of neurofilament, vimentin and α‐smooth‐muscle actin were demonstrated by indirect immunofluorescence. In the KP‐MRT‐NS cell line, the expression of neurofilament, α‐smooth‐muscle actin, basic calponin and smooth‐muscle‐myosin heavy chain of SM1 and SM2 isoforms was revealed by immunofluorescence, Western blot and/or reverse transcriptase‐polymerase chain reaction (RT‐PCR). MyoD1 mRNA, determined as a skeletal‐muscle‐cell lineage marker, was not expressed in the primary‐tumor tissue or in the KP‐MRT‐NS cell line. According to our findings, the MRT cells are of both neural and smooth‐muscle cell phenotypes, and support the neural‐crest origin of MRT. Int. J. Cancer 82:678–686, 1999.

Consensus guideline for diagnosis and treatment of childhood idiopathic thrombocytopenic purpura.

A practice guideline aimed at standardizing the treatment for childhood idiopathic thrombocytopenic purpura (ITP) is presented. This consensus guideline is based on a survey carried out via a questionnaire prepared by the ITP Committee of the Japanese Society of Pediatric Hematology and sent to society members. The survey questionnaire included questions on the diagnosis of ITP submitted for the purpose of revising the ITP diagnostic guideline prepared in 1990 by the Research Group for Intractable Hematopoietic Disorders; a revised diagnostic guideline also is presented.

Malignant transformation in craniopharyngioma after radiation therapy: a case report and review of the literature.

OBJECTIVE Craniopharyngioma is a benign epithelial tumor that is thought to arise from the remnant of the Rathke pouch. Malignant transformation in craniopharyngioma is extremely rare. Herein, we report a case of malignant transformation in craniopharyngioma after radiation therapy. MATERIALS AND METHODS Histopathological and immunohistochemical analyses were carried out for specimens of the suprasellar tumor (from three resections, with the third surgery performed after radiation therapy). RESULTS The resected tumors from the first and second surgeries comprised islands of loosely cohesive aggregates of epithelial cells, so-called stellate reticulum. At the periphery of the nests, palisaded columnar epithelium was observed. Wet keratins were scattered, and few mitotic figures were seen. The third surgical specimen was composed of irregular large nests of basaloid cells that had large, round to oval nuclei with prominent nucleoli, and mitotic figures were frequently seen (21/10 high power fields). In the center of the nests, eosinophilic ghost cells, resembling wet keratin, were observed. Accordingly, the diagnosis of malignant transformation in craniopharyngioma was made. Immunohistochemical studies revealed that the p53 protein was over-expressed in the malignant component, whereas its expression was much lower in the benign component. CONCLUSIONS Similar to the ten previously reported cases of malignant transformation in craniopharyngioma, the present case occurred after radiation therapy. p53 protein overexpression was also observed in the earlier cases of malignant craniopharyngioma as well as in the present case (6/6 cases). We concluded that radiation therapy and p53 mutations could be involved in malignant transformation in craniopharyngioma.

Relief of chronic burning pain in Fabry disease with neurotropin

Neurotropin, an extract from the inflamed skin of vaccinia virus-inoculated rabbits, was effective in the relief of sharp or burning pain induced by pyrexia, hot weather, bathing, or exercise in 2 siblings with Fabry disease. Neither neurotropin nor carbamazepine mono-therapy relieved the episodic colicky pain in 1 patient; however, therapy with both drugs eliminated the pain completely. This result suggests that the mechanisms underlying the analgesic actions of both drugs may be complementary in ameliorating the pain of Fabry disease, even though the mechanism underlying the pain has not been clearly elucidated.