伴有髓系分化抗原表达的神经母细胞瘤骨髓转移1例并文献复习

目的：报道伴有髓系抗原表达的神经母细胞瘤骨髓转移患儿1例,并进行文献复习。方法：取患者骨髓液进行细胞形态学分析及流式细胞术检测细胞分化抗原。结果：该患者骨髓形态学考虑为神经母细胞瘤髓内转移,经流式细胞术分析异常细胞同时表达髓系分化抗原CD13、CD15和CD11b,结合影像学检查确诊为神经母细胞瘤（Ⅳ期）。结论：复习相关文献并结合本例报道发现神经母细胞瘤细胞和造血细胞拥有一些相同的抗原决定簇,可伴有髓系及淋巴系分化抗原的表达,但其在神经母细胞瘤的分化程度、临床分期、疗效及预后判断上的作用尚需进一步研究。     

儿童小脑髓母细胞瘤几种标记物的免疫组化表达分析

目的 :研究儿童髓母细胞瘤的组织发生和Ki67、p5 3、C erbB 2与其发生及预后的关系。方法 :采用SP免疫组化法检测 7例正常小脑、2 2例髓母细胞瘤Ki67、p5 3、C erbB 2、GFAP和NSE的表达。结果 :髓母细胞瘤中GFAP、NSE表达率分别为 45 5 %、5 9 1%。髓母细胞瘤中Ki67、p5 3和C erbB 2的表达率显著高于正常小脑 ,P <0 0 5。未分化组、经典型、肿瘤直径 >5cm组髓母细胞瘤Ki67、p5 3高表达 ,P <0 0 5 ;C erbB 2则与肿瘤坏死和肿瘤大小有关 ,P <0 0 5。结论 :髓母细胞瘤起源于原始神经外胚叶组织 ,具有双向分化潜能。Ki67、p5 3和C erbB 2与髓母细胞瘤的发生及预后有关     

髓母细胞瘤CT诊断(附93例报告)

目的探讨CT对髓母细胞瘤的诊断价值.方法对93例髓母细胞瘤的CT表现与手术病理对照进行回顾性分析,93例患者全部行CT检查,其中65例经MRI检查,全部病例经手术及病理证实.结果髓母细胞瘤好发于10岁以下儿童（88%）,且肿瘤位于小脑蚓部,成人则常发生在一侧小脑半球.肿瘤血运较丰富,可有囊变、坏死（25%）,偶有钙化（7%）.其影像学特点是肿瘤呈高或略高密度肿块影,有中等度较均一增强,有8%增强不显著.结论髓母细胞瘤恶性度高、预后差,其CT表现有一定的特异性.     

成人髓母细胞瘤2例报告

髓母细胞瘤(Medulloblastoma)多发生在小儿,尤以学龄儿童多见,在成人较为少见。然而,成人髓母细胞瘤又有其不同于小儿髓母细胞瘤的特点。笔者近日遇到两例,并为其手术。现报告如下。     

螺旋断层放疗治疗髓母细胞瘤的疗效观察

目的 探讨螺旋断层放疗技术治疗髓母细胞瘤的剂量学优势、不良反应及疗效。方法 2011年2月至2011年10月,4例髓母细胞瘤患者接受螺旋断层放射治疗。术后瘤床临床靶区（CTV1）剂量：50.4Gy／28f,每次18Gy,5次／周;全脑全脊髓临床靶区（CTV2）剂量：30.6Gy／17f,每次1.8Gy,5次／周。结果 4例患者接受照射的均匀性和适形性较好,重要器官的照射剂量低,治疗时间均小于15min。4例患者均获随访,中位随访9个月（4～15个月）,至随访截止时间无1例复发。主要不良反应为骨髓抑制和恶心呕吐,4例患者均可耐受。结论 螺旋断层放疗治疗髓母细胞瘤的疗效和剂量分布较好,为治疗髓母细胞瘤开辟了一个新的治疗平台。     

儿童脑肿瘤致癌基因的扩增

脑肿瘤是儿童最常见的实质性肿瘤。儿童脑肿瘤的细胞遗传学和分子生物学研究通常只涉及髓母细胞瘤。髓母细胞瘤中染色体数量改变较少,但结构异常较为常见。其异常除了非相互易位及缺失外,还包括i(17q),t(8;11),22p+,11q+等。作者发现原发性及细胞系的髓母细胞瘤均呈有双细微染色体。由此说明上述肿瘤均有基因扩增。     

髓母细胞瘤治疗进展

髓母细胞瘤多发生于青少年和儿童,约占儿童脑肿瘤的30%,成人中枢神经系统肿瘤的3%;髓母细胞瘤恶性程度较高,单纯手术不易完全切除;同时髓母细胞瘤对放化疗多比较敏感,目前标准治疗方案是进行手术,然后接受放疗和化疗。近年来,许多研究者对术后放化疗的方案进行了大量的研究,希望能够在保证较好的疗效的前提下,减少患者的副反应。本文对近年来术后放化疗方案的研究进展进行综述。     

髓母细胞瘤的CT诊断(附50例分析)

 目前CT在诊断髓母细胞瘤方面虽有经验，但也经常遇到一些非典型CT表现的特殊病例误诊为其他颅内肿瘤。为进一步提高髓母细胞瘤的CT诊断水平，对经CT检查，并经手术病理证实的50例髓母细胞瘤总结如下。     

成年人小脑髓母细胞瘤椎管内转移一例并文献复习

 【摘要】　目的　分析成年人髓母细胞瘤的临床病理特点及其转移和预后的影响因素。方法　观察1例成年人小脑半球髓母细胞瘤的组织病理学形态及免疫组织化学染色情况。结果　组织学类型为促纤维增生型,免疫组织化学染色肿瘤细胞显示CD99（+／-）、波形蛋白（Vimentin）（+／-）、胶质纤维酸性蛋白（GFAP）约5 %阳性、增殖细胞核抗原（Ki-67）约20 %阳性,而突触素（Syn）、神经特异性烯醇化酶（NSE）、神经纤维丝蛋白（NF）、S-100蛋白、细胞角蛋白（CK）和上皮细胞膜抗原（EMA）均为（-）。术后3年发生椎管内转移。结论　成年人髓母细胞瘤术后转移与多种因素有关,其中手术方式及辅助治疗方案尤为关键。     

HO-1和Nrf-2在髓母细胞瘤中的表达和意义

  目的  髓母细胞瘤是儿童后颅凹常见恶性肿瘤, 本研究目的在于检测Nrf-2和HO-1在髓母细胞瘤中的表达, 并探讨其在髓母细胞瘤发生发展的意义。  方法  应用免疫组化SP法检测41例髓母细胞瘤及27例瘤旁对照脑组织中Nrf-2和HO-1的表达, 并结合研究病例的临床资料(患者性别、年龄、临床症状、肿瘤大小、肿瘤病理分型), 进行相关性分析。  结果  在髓母细胞瘤病例中, Nrf-2和HO-1的阳性表达率(分别为82.9%, 78.0%)与瘤旁对照组织的阳性表达率(分别为37.0%, 29.6%)相比明显升高, 差异具有显著统计学意义(P < 0.001), 并且二者之间呈显著正相关关系(P < 0.05)。但Nrf-2和HO-1的表达与分析的病例的临床特征无显著相关性(P > 0.05)。  结论  Nrf-2和HO-1的高表达可能在髓母细胞瘤的发生发展中发挥重要作用。      

MicroRNA profiling in human medulloblastoma

Medulloblastoma is an aggressive brain malignancy with high incidence in childhood. Current treatment approaches have limited efficacy and severe side effects. Therefore, new risk-adapted therapeutic strategies based on molecular classification are required. MicroRNA expression analysis has emerged as a powerful tool to identify candidate molecules playing an important role in a large number of malignancies. However, no data are yet available on human primary medulloblastomas. A high throughput microRNA expression profiles was performed in human primary medulloblastoma specimens to investigate microRNA involvement in medulloblastoma carcinogenesis. We identified specific microRNA expression patterns which distinguish medulloblastoma differing in histotypes (anaplastic, classic and desmoplastic), in molecular features (ErbB2 or c-Myc overexpressing tumors) and in disease-risk stratification. MicroRNAs expression profile clearly differentiates medulloblastoma from either adult or fetal normal cerebellar tissues. Only a few microRNAs displayed upregulated expression, while most of them were downregulated in tumor samples, suggesting a tumor growth-inhibitory function. This property has been addressed for miR-9 and miR-125a, whose rescued expression promoted medulloblastoma cell growth arrest and apoptosis while targeting the proproliferative truncated TrkC isoform. In conclusion, misregulated microRNA expression profiles characterize human medulloblastomas, and may provide potential targets for novel therapeutic strategies.     

MicroRNA-31 suppresses medulloblastoma cell growth by inhibiting DNA replication through minichromosome maintenance 2

Medulloblastoma is an aggressive childhood brain tumor with poor prognosis. Recent studies indicate that dys-regulation of microRNA expression plays important roles in tumorigenesis. By comparing microRNA levels between mouse medulloblastoma and normal cerebellar tissues, we identified a set of down-regulated microRNAs including miR-31. Here, we show that the genomic region surrounding human miR-31 at 9p21.3 is frequently deleted in many solid tumor cell lines, and reintroducing miR-31 into DAOY cells, a line of human medulloblastoma cells devoid of miR-31, strongly suppresses cell growth, causes cell cycle arrest at the G1/S boundary, and inhibits colony formation in vitro and xenograft tumorigenesis in nude mice. Global gene expression profiling of mouse medulloblastomas and bioinformatics analyses of microRNA targets suggest that minichromosome maintenance complex component 2 (MCM2) is a likely target gene of miR-31 in suppressing cell growth. We demonstrate that miR-31 inhibits MCM2 expression via its 3''-untranslated region, that knockdown of MCM2 in DAOY cells leads to a degree of growth inhibition comparable to that by miR-31 restoration, and that overexpression of miR-31 reduces the chromatin loading of MCM2 at the point of G1/S transition. Taken together, these data indicate that miR-31 suppresses medulloblastoma tumorigenesis by negatively regulating DNA replication via MCM2.     

Transgenerational inheritance of enhanced susceptibility to radiation-induced medulloblastoma in newborn Ptch1+/? mice after paternal irradiation

The hypothesis of transgenerational induction of increased cancer susceptibility after paternal radiation exposure has long been controversial because of inconsistent results and the lack of a mechanistic interpretation. Here, exploiting Ptch1 heterozygous knockout mice, susceptible to spontaneous and radiation-induced medulloblastoma, we show that exposure of paternal germ cells to 1 Gy X-rays, at the spermatogonial stage, increased by a considerable 1.4-fold the offspring susceptibility to medulloblastoma induced by neonatal irradiation. This effect gained further biological significance thanks to a number of supporting data on the immunohistochemical characterization of the target tissue and preneoplastic lesions (PNLs). These results altogether pointed to increased proliferation of cerebellar granule cell precursors and PNLs cells, which favoured the development of frank tumours. The LOH analysis of tumor DNA showed Ptch1 biallelic loss in all tumor samples, suggesting that mechanisms other than interstitial deletions, typical of radiation-induced medulloblastoma, did not account for the observed increased cancer risk. This data was supported by comet analysis showing no differences in DNA damage induction and repair in cerebellar cells as a function of paternal irradiation. Finally, we provide biological plausibility to our results offering evidence of a possible epigenetic mechanism of inheritance based on radiation-induced changes of the microRNA profile of paternal sperm.     

The role of the membrane cytoskeleton cross-linker ezrin in medulloblastoma cells

Medulloblastoma is a highly malignant brain tumor that occurs predominantly in children. The molecular pathogenesis of medulloblastoma is under investigation. Previously, we used complementary DNA micro-array analysis to compare patterns of gene expression in medulloblastoma samples versus normal cerebellum. The cytoskeletal protein ezrin was found to be overexpressed in medulloblastoma compared with normal cerebellum, an observation that was further validated by immunohistochemistry and real-time PCR analysis. To assess the role of ezrin in medulloblastoma, we studied ezrin’s role in medulloblastoma migration, invasion, and adhesion. Western blotting and immunofluorescence showed high expression of ezrin in four medulloblastoma cell lines, and ezrin was primarily localized to filopodia. Ezrinspecific small interfering RNA suppressed the formation of filopodia and in vitro migration, invasion, and adhesion. We also used a stably transfected medulloblastoma cell line to study the effect of ezrin overexpression. We showed that high expression of ezrin promotes filopodia formation and in vitro invasion. Finally, athymic mice implanted with ezrin-overexpressing DAOY medulloblastoma cell clones in the cerebellum showed shortened survival compared with controls. These findings suggest that, in addition to other cytoskeletal proteins, ezrin plays an important role in medulloblastoma adhesion, migration, and invasion.     

Response of preclinical medulloblastoma models to combination therapy with 13-cis retinoic acid and suberoylanilide hydroxamic acid (SAHA)

Medulloblastoma is the most common malignant brain tumor of children, and more specific and effective therapeutic management needs to be developed to improve upon existing survival rates and to avoid side-effects from current treatment. Gain of chromosome seven is the most frequent chromosome copy number aberration in medulloblastoma, suggesting that overexpression of genes on chromosome seven might be important for the pathogenesis of medulloblastoma. We used microarrays to identify chromosome seven genes overexpressed in medulloblastoma specimens, and validated using data from published gene expression datasets. The gene encoding the alpha 2 subunit of type I collagen, COL1A2, was overexpressed in all three datasets. Immunohistochemistry of tumor tissues revealed type I collagen in the leptomeninges, and in the extracellular matrix surrounding blood vessels and medulloblastoma cells. Expression of both type I collagen and the β1 subunit of integrin, a subunit of a known type I collagen receptor, localized to the same area of medulloblastoma. Adherence of D283 medulloblastoma cells to type I collagen matrix in vitro depends on the β1 subunit of integrin. Because medulloblastoma is characteristic of high vascularity, and because inhibition of type I collagen synthesis has been shown to suppress angiogenesis and tumor growth, our data suggest that type I collagen might be a potential therapeutic target for treating medulloblastoma. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

HDM2 promotes WIP1-mediated medulloblastoma growth

Medulloblastoma is the most common malignant childhood brain tumor. The protein phosphatase and oncogene WIP1 is over-expressed or amplified in a significant number of primary human medulloblastomas and cell lines. In the present study, we examine an important mechanism by which WIP1 promotes medulloblastoma growth using in vitro and in vivo models. Human cell lines and intracerebellar xenografted animal models were used to study the role of WIP1 and the major TP53 regulator, HDM2, in medulloblastoma growth. Stable expression of WIP1 enhances growth of TP53 wild-type medulloblastoma cells, compared with cells with stable expression of an empty-vector or mutant WIP1. In an animal model, WIP1 enhances proliferation and reduces the survival of immunodeficient mice bearing intracerebellar xenografted human medulloblastoma cells. Cells with increased WIP1 expression also exhibit increased expression of HDM2. HDM2 knockdown or treatment with the HDM2 inhibitor Nutlin-3a, the active enantomer of Nutlin-3, specifically inhibits the growth of medulloblastoma cells with increased WIP1 expression. Nutlin-3a does not affect growth of medulloblastoma cells with stable expression of an empty vector or of mutant WIP1. Knockdown of WIP1 or treatment with the WIP1 inhibitor CCT007093 results in increased phosphorylation of known WIP1 targets, reduced HDM2 expression, and reduced growth specifically in WIP1 wild-type and high-expressing medulloblastoma cells. Combined WIP1 and HDM2 inhibition is more effective than WIP1 inhibition alone in blocking growth of WIP1 high-expressing medulloblastoma cells. Our preclinical study supports a role for therapies that target WIP1 and HDM2 in the treatment of medulloblastoma.     

The PI3K inhibitor GDC-0941 displays promising in vitro and in vivo efficacy for targeted medulloblastoma therapy

Deregulation of the Phosphoinositide 3-kinase (PI3K)/AKT signalling network is a hallmark of oncogenesis. Also medulloblastoma, the most common malignant brain tumor in children, is characterized by high levels of AKT phosphorylation and activated PI3K signalling in medulloblastoma is associated with enhanced cellular motility, survival and chemoresistency underscoring its role of as a potential therapeutic target. Here we demonstrate that GDC-0941, a highly specific PI3K inhibitor with good clinical tolerability and promising anti-neoplastic activity in adult cancer, also displays anti-proliferative and pro-apoptotic effects in pediatric human medulloblastoma cell lines. Loss in cell viability is accompanied by reduced phosphorylation of AKT, a downstream target of PI3K. Furthermore, we show that GDC-0941 attenuates the migratory capacity of medulloblastoma cells and targets subpopulations expressing the stem cell marker CD133. GDC-0941 also synergizes with the standard medulloblastoma chemotherapeutic etoposide. In an orthotopic xenograft model of the most aggressive human medulloblastoma variant we document that oral adminstration of GDC-0941 impairs tumor growth and significantly prolongs survival. These findings provide a rational to further investigate GDC-0941 alone and in combination with standard chemotherapeutics for medulloblastoma treatment.     

Robust infectivity and replication of Delta-24 adenovirus induce cell death in human medulloblastoma

The diverse advanced treatment modalities currently available to children with medulloblastoma, including surgery and radiotherapy, are associated with deleterious side effects and often with an unfavorable prognosis. A mutant adenovirus, Delta-24, which has a 24-base pair deletion in the Rb-binding region of the E1A gene, demonstrates selective replication and oncolysis in various malignant phenotypes. Here we report the ability of Delta-24 to kill medulloblastoma cells. Flow cytometric analyses of cell receptors demonstrated expression of the coxsackie adenovirus receptor and RGD-related integrins in the assessed medulloblastoma cell lines. Infectivity assays using a replication-deficient adenovirus to transduce the green fluorescence protein gene showed that the Delta-24 adenovirus infects 99% of Daoy and 46% of D283 Med medulloblastoma cells at a multiplicity of infection (MOI) of 50. Within 4 days after infecting medulloblastoma cells with Delta-24, a noticeable cytopathic effect was produced. Delta-24 induced a total cytopathic effect in Daoy and D283 Med medulloblastoma cells after 6 and 8 days of infection, respectively. In the infected population of cells, cell death correlated with the accumulation of cells in the S phase. At 5 days post-infection with 2.5 MOIs of Delta-24 adenovirus, the percentage of Daoy medulloblastoma cells in the S phase increased to 71.9+/-5.5%, compared with control values of 20.5+/-1.4%. The release of viral progeny was quantified as being increased by two orders of magnitude, indicating efficient replication of Delta-24 in medulloblastoma cells. This is the first report of the ability of oncolytic adenoviruses to infect and kill medulloblastoma cells, the findings of which suggest the potential efficacy of Delta-24 as a therapy for human medulloblastoma tumors.