综述与专论: 脊髓星形细胞瘤研究进展

脊髓星形细胞瘤是一种罕见的中枢神经系统恶性肿瘤,在流行病学、肿瘤临床学表型、分子遗传标记、治疗及研究方面有着独特特征。虽然随着手术技术的进步以及分子病理的发展,脑胶质瘤的研究和治疗取得较大进展,但脊髓星形细胞瘤的研究和治疗却发展缓慢。其原因一方面在于临床样本较少,难以开展研究,另一方面因其分子遗传独特性,对脑胶质瘤一线化疗药替莫唑胺敏感性差。因而亟需理清脊髓星形细胞瘤的研究现状,为改善其临床疗效梳理潜在方向。基于此,本文综述脊髓星形细胞瘤的临床特征、病理分型、分子遗传特征和当前治疗方法等方面的研究进展,在描绘脊髓星形细胞瘤的临床治疗现状和研究进展的基础上,提出了未来研究和治疗潜在方向。     

Lectins as differentiation markers of human gliomas.

The lectins Concanavalin A (Con A), Ricinus communis agglutinin (RCA-I), Peanut agglutinin (PNA) and Wheat germ agglutinin (WGA) as well as the immunomarkers for glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) were used in a series of 21 glial tumors (4 pylocytic astrocytomas, 5 grade II astrocytomas, 3 anaplastic astrocytomas, 4 glioblastomas and 5 oligodendrogliomas). ConA binds to all tumoral astrocytes in low grade astrocytomas, as well as to well differentiated tumoral astrocytes in anaplastic astrocytomas and glioblastomas. RCA-I has a similar behaviour. PNA, and to a lesser degree WGA, binds selectively to the oligodendroglial plasma membrane in well differentiated oligodendrogliomas. The results suggest that these lectins are markers of differentiation in gliomas rather than of malignancy.     

The expression of the epitope H recognized by the monoclonal antibody H is higher in astrocytomas compared to anaplastic astrocytomas and glioblastomas

The epitope H contains an O-linked N-acetylglucosamine residue in a specific conformation and/or environment recognized by the monoclonal antibody H (mAbH). mAbH stains two bands with Mr x0.001 of 209 and 62 in lysates of cultured rat astrocytes. In normal human brains epitope H is absent from the overwhelming majority of normal astrocytes and only sparse reactivity is observed, confined mostly to fibrous astrocytes. Upregulation of the epitope H takes place in reactive astrocytes. In the present study we used the mAbH to investigate the immunohistochemical expression of the epitope H in 41 cases of astrocytic tumors including 19 cases of astrocytomas, 8 cases of anaplastic astrocytomas and 14 cases of glioblastomas. Seven out of 19 cases (37%) of astrocytomas showed weak staining, 10 cases (53%) moderate staining and 2 cases (10%) intense staining. Two out of 8 cases (25%) of anaplastic astrocytomas appeared negative, 3 cases (37.5%) showed weak staining and 3 cases (37.5%) moderate staining. Four out of 14 cases (28.5) of glioblastomas appeared negative, 7 cases (50%) showed weak staining, 2 cases (14%) showed moderate staining and only one case (7.5%) showed intense staining. There was a statistically significant elevation of the expression of the epitope H in astrocytomas compared to anaplastic astrocytomas and glioblastomas (p=0.047). These results indicate that the expression of the epitope H decreases in parallel with the increase of the grade of astrocytic tumors from low to higher grade neoplasms. This could be of interest for predicting the progression of an astrocytic tumor since it is documented that astrocytomas progress to tumors of higher grade of malignancy. Further investigation of the antigens bearing the epitope H might help to gain further insight into the mechanisms which regulate the progression of astrocytic tumors and to examine the relevance of the mAbH staining with respect to the prognosis of these neoplasms.     

Identification of COL6A1 as a differentially expressed gene in human astrocytomas

Diffuse infiltrating gliomas are the most common tumors of the central nervous system. Gliomas are classified by the WHO according to their histopathological and clinical characteristics into four classes: grade I (pilocytic astrocytoma), grade II (diffuse astrocytoma), grade III (anaplastic astrocytoma), and grade IV (glioblastoma multiforme). Several genes have already been correlated with astrocytomas, but many others are yet to be uncovered. By analyzing the public SAGE data from 21 patients, comprising low malignant grade astrocytomas and glioblastomas, we found COL6A1 to be differentially expressed, confirming this finding by real time RT-PCR in 66 surgical samples. To the best of our knowledge, COL6A1 has never been described in gliomas. The expression of this gene has significantly different means when normal glia is compared with low-grade astrocytomas (grades I and II) and high-grade astrocytomas (grades III and IV), with a tendency to be greater in higher grade samples, thus rendering it a powerful tumor marker.     

A Molecular Predictor Reassesses Classification of Human Grade II/III Gliomas

Diffuse gliomas are incurable brain tumors divided in 3 WHO grades (II; III; IV) based on histological criteria. Grade II/III gliomas are clinically very heterogeneous and their prognosis somewhat unpredictable, preventing definition of appropriate treatment. On a cohort of 65 grade II/III glioma patients, a QPCR-based approach allowed selection of a biologically relevant gene list from which a gene signature significantly correlated to overall survival was extracted. This signature clustered the training cohort into two classes of low and high risk of progression and death, and similarly clustered two external independent test cohorts of 104 and 73 grade II/III patients. A 22-gene class predictor of the training clusters optimally distinguished poor from good prognosis patients (median survival of 13–20 months versus over 6 years) in the validation cohorts. This classification was stronger at predicting outcome than the WHO grade II/III classification (P≤2.8E-10 versus 0.018). When compared to other prognosis factors (histological subtype and genetic abnormalities) in a multivariate analysis, the 22-gene predictor remained significantly associated with overall survival. Early prediction of high risk patients (3% of WHO grade II), and low risk patients (29% of WHO grade III) in clinical routine will allow the development of more appropriate follow-up and treatments.     

Toward a molecular classification of the gliomas: histopathology, molecular genetics, and gene expression profiling

As many as 100,000 new cases of brain tumor are diagnosed each year in the United States. About half of these are primary gliomas and the remaining half are metastatic tumors and non-glial primary tumors. Currently, gliomas are classified based on phenotypic characteristics. Recent progress in the elucidation of genetic alterations found in gliomas have raised the exciting possibility of using genetic and molecular analyses to resolve some of the problematic issues currently associated with the histological approach to glioma classification. Recently, immunohistochemical studies using novel proliferation markers have significantly advanced the assessment of tumor growth potential and the grading criteria of some tumor subtypes. Preliminary studies using cDNA array technologies suggest that the profiling of gene expression patterns may provide a novel and meaningful approach to glioma classification and subclassification. Furthermore, cDNA array technologies may also be used to identify candidate genes involved in glioma tumor development, invasion, and progression. This review summarizes current glioma classification schemes that are based on histopathological characteristics and discusses the potential for using cDNA array technology in the molecular classification of gliomas.     

脑胶质瘤组织CMTM1、ME2表达与临床病理特征和复发的关系研究

摘要 目的：探讨脑胶质瘤组织含CKLF样MARVEL跨膜结构域的蛋白1（CMTM1）、苹果酸酶2（ME2）表达与临床病理特征和复发的关系。方法：选取2018年1月～2021年1月徐州医科大学附属医院接受切除手术的92例脑胶质瘤患者，根据术后是否复发分为复发组和未复发组。采用免疫组化法检测脑胶质瘤组织和瘤旁组织CMTM1、ME2表达，分析二者与临床病理特征的关系，采用多因素Logistic回归分析脑胶质瘤患者术后复发的影响因素。结果：与瘤旁组织比较，脑胶质瘤组织中CMTM1、ME2阳性表达率升高（P＜0.05）。不同分化程度、世界卫生组织（WHO）中枢神经系统肿瘤分类脑胶质瘤组织中CMTM1、ME2阳性表达率比较，差异有统计学意义（P＜0.05）。随访2年，92例脑胶质瘤患者术后复发率为47.83%（44/92）。多因素Logistic回归分析显示，低分化、WHO中枢神经系统肿瘤分类Ⅲ～Ⅳ级、部分切除和CMTM1、ME2阳性表达为脑胶质瘤患者术后复发的独立危险因素（P＜0.05）。结论：脑胶质瘤组织中CMTM1、ME2阳性表达率升高，与分化程度、WHO中枢神经系统肿瘤分类等级和术后复发有关，可能成为脑胶质瘤患者术后复发的辅助评估指标。     

A modern reproducible method for the histologic grading of astrocytomas with statistical classification tools

OBJECTIVE: To investigate whether statistical classification tools can infer the correct World Health Organization (WHO) grade from standardized histologic features in astrocytomas and how these tools compare with GRADO-IGL, an earlier computer-assisted method. STUDY DESIGN: A total of 794 human brain astrocytomas were studied between January 1976 and June 2005. The presence of 50 histologic features was rated in 4 categories from 0 (not present) to 3 (abundant) by visual inspection of the sections under a microscope. All tumors were also classified with the corresponding WHO grade between I and IV. We tested the prediction performance of several statistical classification tools (learning vector quantization [LVQ], supervised relevance neural gas [SRNG], support vector machines [SVM], and generalized regression neural network [GRNN]) for this data set. RESULTS: The WHO grade was predicted correctly from histologic features in close to 80% of the cases by 2 modern classifiers (SRNG and SVM), and GRADO-IGL was predicted correctly in > 84% of the cases by a GRNN. CONCLUSION: A standardized report, based the 50 histologic features, can be used in conjunction with modern classification tools as an objective and reproducible method for histologic grading of astrocytomas.     

研究报告: 第五版《世界卫生组织中枢神经系统肿瘤分类指南》下成人胶质瘤诊断及预后

目的 脑胶质瘤是最常见的恶性原发性中枢神经系统肿瘤,近年来分子病理的快速发展对胶质瘤诊断及分级带来了重要影响,在2021年发布的《世界卫生组织中枢神经系统肿瘤分类指南》（第五版）引入了更多分子指标对肿瘤的诊断和分级进行指导。本研究旨在临床队列中比较最新版指南和上一版指南对肿瘤诊断及预后评估的影响,以期为临床实践活动中新版指南的应用提供数据参考和依据。方法 回顾性纳入了癌症基因组图谱数据库512例胶质瘤样本,分别依据2016版和2021版《世界卫生组织中枢神经系统肿瘤分类指南》进行诊断、通过Kaplan-Meier进行生存曲线绘制和中位总生存期计算和生存差异分析。结果 对512例样本分别完成了上一版指南和最新版指南的诊断及分级。在新版指南下分别有53和72例异柠檬酸脱氢酶（IDH）突变型和IDH野生型的胶质瘤诊断级别升级为了4级,且这些诊断级别升高的胶质瘤的预后更差。结论 最新版指南较上一版指南可对胶质瘤进行更为精准地分类及分级,在有条件的情况下应尽快依据最新版指南开展诊断及分级。     

Epithelial differentiation in gliomas,meningiomas and choroid plexus papillomas

The immunohistological findings using antibodies to different intermediate filaments (glial fibrillary acidic protein, vimentin and two types of cytokeratin) and epithelial membrane antigen are described in 89 gliomas, 19 meningiomas and 8 choroid plexus papillomas (CPPs) from adult patients. All the patients had total or subtotal surgical excision of their tumours with clinical follow up for between 3 and 7 years. The immunohistological results were correlated with the histological features and patient survival. Tumours other than low grade astrocytomas, oligodendrogliomas and anaplastic ependymomas expressed one or more epithelial markers. This immunohistological evidence of epithelial differentiation in the absence of histological epithelial features in gliomas confirms that the two are not necessarily correlated. It is concluded that the expression of epithelial markers in some intradural tumours may reflect aberrant differentiation related to the degree of anaplasia in poorly differentiated astrocytomas and glioblastomas. All the patients with anaplastic epithelial marker-positive gliomas died within 1 year, whereas only 68% of patients with marker-negative tumours died within the follow-up period. In ependymomas and meningiomas, the expression of epithelial markers may reflect their histogenesis, while in malignant CPPs such expression could denote either their aberrant differentiation or histogenetic derivation.     

Linkage disequilibrium of three polymorphic RFLP markers in the apolipoprotein AI-CIII gene cluster on chromosome 11

A panel of glial tumors consisting of 11 low grade gliomas, 9 anaplastic gliomas, and 29 glioblastomas were analyzed for loss of heterozygosity by examining at least one locus for each chromosome. The frequency of allele loss was highest among the glioblastomas, suggesting that genetic alterations accumulate during glial tumor development. The most common genetic alteration detected involved allele losses of chromosome 10 loci; these losses were observed in all glioblastomas and in three of the anaplastic gliomas. In order to delineate which chromosome 10 region or regions were deleted in association with glial tumor development, a deletion mapping analysis was performed, and this revealed the partial loss of chromosome 10 in eight glioblastomas and two of the anaplastic gliomas. Among these cases, three distinct regions of chromosome 10 were indicated as being targeted for deletion: one telomeric region on 10p and both telomeric and centromeric locations on 10q. These data suggest the existence of multiple chromosome 10 tumor suppressor gene loci whose inactivation is involved in the malignant progression of glioma.     

A MiRNA Signature for Defining Aggressive Phenotype and Prognosis in Gliomas

Gliomas represent a disparate group of tumours for which there are to date no cure. Thus, there is a recognized need for new diagnostic and therapeutic approaches based on increased understanding of their molecular nature. We performed the comparison of the microRNA (miRNA) profile of 8 WHO grade II gliomas and 24 higher grade tumours (2 WHO grade III and 22 glioblastomas) by using the Affymetrix GeneChip miRNA Array v. 1.0. A relative quantification method (RT-qPCR) with standard curve was used to confirm the 22 miRNA signature resulted by array analysis. The prognostic performances of the confirmed miRNAs were estimated on the Tumor Cancer Genome Atlas (TCGA) datasets. We identified 22 miRNAs distinguishing grade II gliomas from higher grade tumours. RT-qPCR confirmed the differential expression in the two patients'' groups for 13 out of the 22 miRNAs. The analysis of the Glioblastoma Multiforme (GBM) and Lower Grade Glioma (LGG) datasets from TCGA demonstrated the association with prognosis for 6 of those miRNAs. Moreover, in the GBM dataset miR-21 and miR-210 were predictors of worse prognosis in both univariable and multivariable Cox regression analyses (HR 1.19, p = 0.04, and HR 1.18, p = 0.029 respectively). Our results support a direct contribution of miRNAs to glioma cancerogenesis and suggest that miR-21 and miR-210 may play a role in the aggressive clinical behaviour of glioblastomas.     

Biomarkers of clinical responsiveness in brain tumor patients : progress and potential

Gliomas are the most common primary brain tumors in adults. Anaplastic astrocytoma and glioblastoma multiforme represent malignant astrocytomas, which are the most common type of malignant gliomas. Despite research efforts in cancer therapy, the prognosis of patients with malignant gliomas remains poor. Research efforts in recent years have focused on investigating the cellular, molecular, and genetic pathways involved in the progression of malignant gliomas. As a result, biomarkers have emerged as diagnostic, predictive, and prognostic tools that have the potential to transform the field of brain tumor diagnostics. An increased understanding of the important molecular pathways that have been implicated in the progression of malignant gliomas has led to the identification of potential diagnostic, prognostic, and predictive biomarkers, some bearing clinical implications for targeted therapy. Some of the most promising biomarkers to date include loss of chromosomes 1p/19q in oligodendrogliomas and expression of O-6-methylguanine-DNA methyltransferase (MGMT) or epidermal growth factor receptor (EGFR) status in glioblastomas. Other promising biomarkers in glioma research include glial fibrillary acidic protein, galectins, Kir potassium channel proteins, angiogenesis, and apoptosis pathway markers. Research into the clinical relevance and applicability of such biomarkers has the potential to revolutionize our approach to the diagnosis and treatment of patients with malignant gliomas.     

成人胶质瘤诊断的分子遗传学研究进展

胶质瘤是目前中枢神经系统中常见的恶性肿瘤,由于脑组织的特殊性,胶质瘤呈弥漫浸润性生长,恶性程度高,手术难以完整切除且易复发。2007年(第四版)WHO中枢神经系统肿瘤病理学和遗传学对胶质瘤进行了详细的组织学分类,但是循证医学发现依靠组织学的病理诊断标准并不能对胶质瘤的临床表现和预后评估作出精准的判断。近年来全世界都在开展胶质瘤相关的遗传学研究,许多遗传学分子改变被发现,如异柠檬酸脱氢酶(IDH)突变、染色体1p/19q缺失、TP53突变、ATRX突变和TERT启动子突变等,组织学诊断受到了挑战。因此更多的病理科和神经外科医生结合组织形态和遗传学改变对胶质瘤作出"综合性"诊断,使得病理诊断更接近胶质瘤的生物学本质,以便更精准的指导临床治疗。     

Real-time quantification of the proliferative state in astrocytomas

OBJECTIVE: To evaluate proliferative activity in a set of gliomas and to compare the quantitative data obtained by a real-time processor with the labelling index (LI) and mitotic index (MI). STUDY DESIGN: Ki-67 immunostaining was performed on paraffin-embedded specimens from 42 cases of glioblastomas, 17 cases of anaplastic astrocytomas and 14 cases of low grade astrocytomas. Nuclear positivity was calculated as LI and by a real-time image processor for quantitative evaluation. MI was also calculated at 10 high-power fields. The data obtained from glioblastomas were compared with those from anaplastic and low grade astrocytomas. To all the data was applied the Pearson test to verify the correlation between counting and quantitative values and between proliferative markers and survival. RESULTS: A positive trend from low grade astrocytomas to glioblastomas was found for Ki-67 (LI and quantitative values) and MI, with highly significant differences between the three grades of gliomas considered. A good correlation between LI and quantitative values of Ki-67 was found. Very little relationship resulted between survival and Ki-67 LI. No relationship was found between survival and quantitative values of Ki-67. CONCLUSION: Ki-67 allowed effective separation of astrocytic tumors with different grades of malignancy. Quantitative evaluation of color information by means of a real-time processor proved to be a useful, objective and fast way to obtain readings, useful for grading purposes but not for prognostic evaluation.     

Epidermal growth factor receptor expression in human gliomas

Summary The expression of epidermal growth factor receptor (EGFR) was determined in cryosections of 42 human gliomas using biotinylated epidermal growth factor (B-EGF) and two monoclonal antibodies (mAb) against EGFR. All gliomas were found to express EGFR when examined with B-EGF, whereas 33 expressed EGFR when examined with the two mAbs. The highly malignant gliomas (glioblastomas and anaplastic astrocytomas) had a more heterogeneous staining pattern and a larger proportion of tumour cells staining strongly with B-EGF than did the low-grade gliomas (astrocytomas, oligodendrogliomas, mixed gliomas, and ependymomas). This indicates that high-grade gliomas contain more tumour cells rich in EGFR than do the low-grade gliomas. Reactive astrocytes, ependymal cells, and many types of nerve cells (cerebral cortical pyramidal cells, pyramidal and granular hippocampal cells, Purkinje cells, cerebellar granular cells and neurons in the molecular layer of the cerebellum) expressed EGFR, whereas small neurons and normal glial cells were not found to express EGFR.     

CD9 expression in solid non-neuroepithelial tumors and infiltrative astrocytic tumors.

The tetraspan membrane protein CD9 is normally expressed in the mature myelin sheath and is believed to suppress the metastatic potential of certain human tumors. In this study we identified CD9 in a variety of brain tumors by immunohistochemical (IHC) and immunoblotting analyses. We examined 96 tumor samples and three glioma cell lines in addition to a murine brain tumor model of transplanted glioma cells in CD9-deficient mice and control mice. CD9 was expressed not only in solid non-neuroepithelial tumors but also in infiltrative malignant neuroepithelial tumors. Among the neuroepithelial tumors, high-grade astrocytic tumors, including glioblastomas and anaplastic astrocytomas, showed higher immunoreactivity than low-grade cerebral astrocytomas. Thus, CD9 expression in astrocytic tumors correlated with their malignancy. In the murine brain tumor model, transplanted glioma cells were shown to grow and spread through myelinated areas irrespective of the presence or absence of CD9 expression in the recipient's brain. These results indicate that the CD9 expression of astrocytic tumors plays a significant role in the malignancy independent of CD9 expression in the surrounding tissue. This might be explained by the observation that the CD9 molecule is associated with a mitogenic factor, membrane-anchored heparin-binding epidermal growth factor, which is known to be upregulated in malignant gliomas.     

CD90 is identified as a candidate marker for cancer stem cells in primary high-grade gliomas using tissue microarrays

Although CD90 has been identified as a marker for various kinds of stem cells including liver cancer stem cells (CSCs) that are responsible for tumorigenesis, the potential role of CD90 as a marker for CSCs in gliomas has not been characterized. To address the issue, we investigated the expression of CD90 in tissue microarrays containing 15 glioblastoma multiformes (GBMs), 19 WHO grade III astrocytomas, 13 WHO grade II astrocytomas, 3 WHO grade I astrocytomas and 8 normal brain tissues. Immunohistochemical analysis showed that CD90 was expressed at a medium to high level in all tested high-grade gliomas (grade III and GBM) whereas it was barely detectable in low-grade gliomas (grade I and grade II) and normal brains. Double immunofluorescence staining for CD90 and CD133 in GBM tissues revealed that CD133(+) CSCs are a subpopulation of CD90(+) cells in GBMs in vivo. Flow cytometry analysis of the expression of CD90 and CD133 in GBM-derived stem-like neurospheres further confirmed the conclusion in vitro. The expression levels of both CD90 and CD133 were reduced along with the loss of stem cells after differentiation. Furthermore, the limiting dilution assay demonstrated that the sphere formation ability was comparable between the CD90(+)/CD133(+) and the CD90(+)/CD133(-) populations of GBM neurospheres, which is much higher than that of the CD90(-)/CD133(-) population. We also performed double staining for CD90 and a vascular endothelial cell marker CD31 in tissue microarrays which revealed that the CD90(+) cells were clustered around the tumor vasculatures in high-grade glioma tissues. These findings suggest that CD90 is not only a potential prognostic marker for high-grade gliomas but also a marker for CSCs within gliomas, and it resides within endothelial niche and may also play a critical role in the generation of tumor vasculatures via differentiation into endothelial cells.