Mayumi Higashi

Clinical features of Hirschsprung's disease associated with Down syndrome: a 30-year retrospective nationwide survey in Japan

PURPOSE To identify the clinical features in diagnosis and treatment of Hirschsprungs disease (HD) associated with Down syndrome (DS), the authors retrospectively analyzed data for patients with DS from the past 3 nationwide surveys in Japan. This survey was already approved by the Japanese Society of Pediatric Surgeons. METHODS Patient data were collected in 3 phases-phase I (1978-1982), n = 47; phase II (1988-1992), n = 79; and phase III (1998-2002), n = 90. In total, data on 216 patients (5.6%) of 3852 were collected and analyzed. RESULTS The incidence of DS in patients with HD was 2.9%, 7.1%, and 8.2% in phases I, II, and III, respectively, with a corresponding male/female ratio of 5:1, 2.4:1, and 5:1. The ratio of the extent of aganglionosis was nearly consistent across all phases. In phases I, II, and III, the incidence of total colonic aganglionosis was 2.1%, 0%, and 2.2%; and that of cardiovascular anomalies, 36.1%, 45.6%, and 55.6%; and that of preoperative enterocolitis, 31.0%, 26.6%, and 24.4%. The 2 most common surgical procedures were the Soave procedure, including transanal endorectal pull-through, and Duhamel procedure including Z-shaped anastomosis. The mortality rate decreased over time, from 26.1% in phase I to 11.4% in phase II and 7.8% in phase III. Almost all mortality cases were associated with cardiovascular anomalies: 54.5%, 62.5%, and 85.7% in phases I, II, and III, respectively. CONCLUSIONS The incidence of HD with DS has increased over time. The number of male patients and cardiac anomalies has also increased in the last 10 years. Total colonic aganglionosis was rare. A marked decrease in the overall mortality rate was observed.

Association between the HER2 expression and histological differentiation in Wilms tumor

Human epidermal growth factor receptors (HER) play a critical role in the branching morphogenesis of renal tubules. In the current study, we analyzed the expression of HER2 in Wilms tumor and assessed the role of this gene in the tumorgenesis of Wilms tumor. During the period from 1960 to 2005, 40 patients with Wilms tumor were treated in our department. Twenty-four of those patients (except those with clear cell sarcoma of the kidney and malignant rhabdoid tumor of the kidney) were collected and assessed. The histological component of each Wilms tumor was divided into three categories (epithelial, blastemal, and mesenchymal) and the extent of HER2 protein expression was analyzed immunohistochemically. The normal kidney tissue accompanied with 12 cases of Wilms tumor was also examined. In the normal kidney, HER2 showed a strong immunoreactivity in the cell membranes of the collecting tubules and in the endothelial cells. Of 24 cases, 15 cases showed an epithelial component, while 24 cases had a blastemal component and 21 cases had a mesenchymal component, respectively. Among the 15 specimens with epithelial cell differentiation, eight (53.3%) showed HER2 immunoreactive epithelial cells. HER2 immunoreactive blastemal cells were present in 11 (45.8%) of 24 specimens with blastemal cells. On the other hand, only 3 (14.3%) of 21 specimens containing mesenchymal cells showed HER2 immunoreactivity. These results suggest that the extent of HER2 expression is associated with epithelial differentiation in Wilms tumor. These histological findings may therefore help to explain the development of Wilms tumor from the standpoint of histological differentiation.

Diagnostic value of lectin reactive alpha-fetoprotein for neoinfantile hepatic tumors and malignant germ cell tumors: Preliminary study

Background and Purpose The serum alpha-fetoprotein (AFP) level has been used as a tumor marker for hepatoblastoma, and malignant germ cell tumors in pediatric patients. The AFP has 3 isoforms (L1, L2, L3), and the usefulness of the L3 fraction as a diagnostic marker for the adult hepatocellular carcinoma is well known. However, there are few reports dealing with various pediatric malignant tumors. In the current study, we analyzed the diagnostic value of AFP fractions for pediatric diseases, in particular, those occurring in the neoinfantile period. Materials and Methods From 2003 to 2006, two cases of hepatoblastoma, and 5 cases of germ cell tumor, all of which were neoinfantile, were treated in our department. In our analytical system (LiBASys), the level of the L3 fraction contains the majority of the L2 fraction. The total AFP (ng/mL) level and the L3 fraction (%) were measured to assess the usefulness of the L3 fraction as a diagnostic marker. Results In all cases of hepatoblastoma and yolk sac tumor, both the total AFP and the L3 fraction were high, either before treatment or in the presence of malignant tumors. Most of the cases of neonatal immature teratoma showed a high total AFP level during the neoinfantile period, however, the L3 fraction was around 10%, and decreased after surgical treatment. Only 1 case of the immature teratoma demonstrated malignant transformation, when the patient was 8 months old. As the total AFP and the AFP-L3 fraction were proportionally elevated, the patient was treated with additional surgical resection and chemotherapy. In the case of neonatal mature teratoma, the L3 fraction was below 0.5%, even when the total AFP level was high. Discussion Our results indicated that the level of the L3 fraction accurately confirmed the existence, or the malignant potential of hepatic tumor or germ cell tumor. The L3 fraction is useful as a tumor marker during the neoinfantile period.

Umbilical crease incision for duodenal atresia achieves excellent cosmetic results

BackgroundThe surgical procedure for treating congenital duodenal atresia has normally been performed by an upper abdominal transverse incision. Recently, duodenoduodenostomy has been attempted using an umbilical crease incision to improve the cosmetic results.MethodsEighteen cases of duodenal obstruction, including 15 atresia, 2 stenosis, and 1 atresia and stenosis, were treated from June 2001 to August 2009, in which 8 cases were performed via the umbilical crease incision and 10 cases via the conventional transverse incision. The clinical records of all cases were evaluated retrospectively.ResultsAll cases underwent radical operation safely. There were no differences in the operating time between the two kinds of incision. Two cases of umbilical crease incision showed minor complications. All the cases operated via the umbilical crease incision achieved a scarless abdomen within a few months after the operation.ConclusionsThe outcome of duodenal atresia is satisfactory with excellent cosmesis after a duodenoduodenostomy performed via the umbilical crease incision.

MEK inhibitors as a novel therapy for neuroblastoma: Their in vitro effects and predicting their efficacy

BACKGROUND A recent study reported that relapsed neuroblastomas had frequent RAS-ERK pathway mutations. We herein investigated the effects and pathways of MEK inhibitors, which inhibit the RAS-ERK pathway, as a new molecular-targeted therapy for refractory neuroblastomas. METHOD Five neuroblastoma cell lines were treated with trametinib (MEK inhibitor) or CH5126766 (RAF/MEK inhibitor). Growth inhibition was analyzed using a cell viability assay. ERK phosphorylation and the MYCN expression were analyzed by immunoblotting or immunohistochemistry. RAS/RAF mutations were identified by direct sequencing or through the COSMIC database. RESULTS Both MEK inhibitors showed growth inhibition effects on cells with ERK phosphorylation, but almost no effect on cells without. In immunoblotting analyses, ERK phosphorylation and MYCN expression were suppressed in ERK active cells by these drugs. Furthermore, phosphorylated-ERK immunohistochemistry corresponded to the drug responses. Regarding the relationship between RAS/Raf mutations and ERK phosphorylation, ERK was phosphorylated in one cell line (NLF) without RAS/Raf mutations. CONCLUSION MEK inhibitors are a promising molecular-targeted therapeutic option for ERK active neuroblastomas. The efficacy of MEK inhibitors corresponds to ERK phosphorylation, while RAS/RAF mutations are not always detected in drug-sensitive cells. Phosphorylated-ERK immunohistochemistry is thus a useful method to analyze ERK activity and predict the therapeutic effects of MEK inhibitors.

Surgical intervention strategies for pediatric congenital cystic lesions of the lungs: A 20-year single-institution experience

BACKGROUND The aim of this study was to assess surgical intervention strategies for congenital cystic lesions of the lungs (CCL), focusing on the safety of lung resection. MATERIALS AND METHODS The clinical features of 27 children (CCAM, n=16; bronchial atresia, n=4; bronchogenic cyst, n=3; pulmonary sequestration, n=3; lobar emphysema, n=1) who were treated at our institution between 1995 and 2014 were analyzed. RESULTS Of the 27 patients, 14 were asymptomatic, and 13 were symptomatic. The youngest symptomatic patient presented with pneumonia at 9months of age. The mean age at surgery was 4months in the asymptomatic group and 4.1years in the symptomatic group. The mean operating time was 167minutes in the asymptomatic group and 275minutes in the symptomatic group (P<0.001). The mean amount of intraoperative bleeding was 15g in the asymptomatic group and 83.4g in the symptomatic group (P<0.05). All of the prenatally diagnosed patients underwent surgery within six months of birth. Three patients had remnant cystic lesions, all of which involved cystic lesions located over the lobulation anomalies of the lung. CONCLUSIONS To minimize surgical invasiveness, surgery for CCL should be performed during the asymptomatic period or within six months after birth.

Tumor-homing effect of human mesenchymal stem cells in a TH-MYCN mouse model of neuroblastoma

BACKGROUND Human mesenchymal stem cells (hMSCs) are multipotent stem-like cells that are reported to have tumor-suppression effects and migration ability toward damaged tissues or tumors. The aim of this study was to analyze the tumor-homing ability of hMSCs and antitumor potency in a transgenic TH-MYCN mouse model of neuroblastoma (NB). METHODS hMSCs (3×106) labeled with DiR, a lipophilic near-infrared dye, were intraperitoneally (i.p.) or intravenously (i.v.) administered to the TH-MYCN mice. hMSC in vivo kinetics were assayed using the IVIS® imaging system for 24h after injection. Immunohistochemistry using human CD90 antibody was also performed to confirm the location of hMSCs in various organs and tumors. Furthermore, the survival curve of TH-MYCN mice treated with hMSCs was compared to a control group administered PBS. RESULTS i.p. hMSCs were recognized in the tumors of TH-MYCN mice by IVIS. hMSCs were also located inside the tumor tissue. Conversely, most of the i.v. hMSCs were captured by the lungs, and migration into the tumors was not noted. There was no significant difference in the survival between the hMSC and control groups. CONCLUSION The present study suggested that hMSCs may be potential tumor-specific therapeutic delivery vehicles in NB according to their homing potential to tumors.

High expressions of neuronatin isoforms in favorable neuroblastoma

Neuroblastoma is a malignant solid tumor of children, which derives from the embryonal sympathoadrenal linage. Clinical cases can vary widely from a favorable to an unfavorable prognosis according to the presence of genetic aberrations, such as MYCN amplification. Our cDNA microarray analysis which compared the gene expressions between favorable and unfavorable neuroblastomas showed a high expression of the neuronatin (Nnat) gene in favorable neuroblastomas. Nnat is highly conserved in mammalian species, and its expression appears in nervous systems from the hindbrain to the peripherals during the prenatal periods. The Nnat mRNA expression, investigated in 63 of neuroblastoma samples by quantitative reverse-transcription polymerase chain reaction, was found to be significantly higher in the favorable prognosis groups than in the unfavorable groups. Nnat is an imprinted gene, and its expression in IMR32 neuroblastoma cell line was up-regulated by treatment with a demethylating agent. High expressions of Nnat isoforms induced in an IMR32 neuroblastoma cell line changed the cell morphology to the extension of the neural processes, which thus indicated the occurrence of cell differentiation. In conclusion, the high expressions of Nnat were found to be associated with good prognoses in neuroblastoma, which might indicate tumor differentiation, and its suppressions in unfavorable tumors are considered to be under epigenetic control.

In vivo effects of short- and long-term MAPK pathway inhibition against neuroblastoma

BACKGROUND/PURPOSE It was reported that almost 80% of relapsed neuroblastomas showed MAPK pathway mutations. In our previous study, both trametinib (MEK inhibitor) and CH5126766 (RAF/MEK inhibitor) showed in vitro antitumor effects on neuroblastoma cells with ERK phosphorylation (pERK). In this study, we analyzed the in vivo effects of MAPK pathway inhibition in neuroblastoma xenografts. METHODS Xenograft mice with IMR5, CHP-212, or SK-N-AS received daily oral administration of either trametinib or CH5126766 for two weeks (short term) or eight weeks (long term). The tumors were measured twice weekly and harvested after treatment for histopathological analyses, including pERK and Ki67 immunohistochemistry. RESULTS In short-term treatment, both inhibitors showed significant growth inhibition in CHP-212 and SK-N-AS xenografts, which were pERK-positive before treatment. The number of pERK- and Ki67-positive cells decreased after treatment. Conversely, IMR5 xenografts, which were pERK-negative, were resistant to treatment. During long-term treatment, SK-N-AS xenografts started to regrow from about six weeks with partial differentiation. pERK-positive cells reincreased in these regrown tumors. CONCLUSIONS MAPK pathway inhibition was effective for treating pERK-positive neuroblastoma in vivo. Therefore, pERK immunohistochemistry might be a convenient biomarker for MAPK pathway inhibition in neuroblastoma treatment. However, neuroblastomas developed acquired drug resistance after long-term treatment. Further studies to overcome acquired resistance are needed.

Thoracoscopic resection for mediastinal thymolipoma in a child: Thoracoscopic resection of thymolipoma

Thymolipoma is a rare disease among benign tumors. We herein report the case of a child who underwent thoracoscopic resection of a large thymolipoma. A 3‐year‐old boy was diagnosed with an anterior mediastinal solid tumor. Thoracic imaging revealed a fat density mass that was 8.0 × 5.0 × 3.5 cm in size. Given the MRI findings of the tumor, we suspected that the lesion was a teratoma. We decided to perform thoracoscopic exploration and, if possible, resection of the solid tumor sequentially. We successfully resected the tumor thoracoscopically. A histological examination revealed thymolipoma. For large mediastinal tumors in the intrathoracic space in children, the thoracoscopic approach is recommended when the tumor is preoperatively considered to be benign and resectable.