AgNORs,p53癌基因蛋白在胶质细胞增生和胶质瘤 …

目的：探讨对核仁组成区嗜银蛋白（ＡｇＮＯＲｓ）ｐ５３蛋白在胶质细胞增生和胶质瘤中的表达。方法：运用免疫组化的形态半定量技术，对胶质细胞增生和星形细胞瘤分别标记ＡｇＮＯＲｓ（３７例）ｐ５３蛋白（３３例）的表达，结果：ＡｇＮＯＲｓｐ５３蛋白在胶质细胞增生和Ｉ级星形细胞瘤以及Ⅱ，Ⅲ，Ⅳ级星形细胞瘤中的表达存在差异性，各组间统计学处理Ｐ〈０．０１，差异有显著性，结论：ＡｇＮＯＲｓ，ｐ５３蛋白可作为鉴别胶质     

星形细胞肿瘤中MDM2蛋白与突变型p53蛋白的表达及其？…

目的：探讨ｍｄｍ－２基因表达和ｐ５３基因突变在星形细胞肿瘤发生发展中的作用及两者的相关性。方法：采用ＳＡＢＣ免疫组化法对１２０例星形细胞肿瘤进行检测。结果：在分化不良性星形细胞瘤及多形性胶质母细胞瘤中，ＭＤＭ２蛋白的阳性率分别为３０．００％和３５．２９％，突变型ｐ５３蛋白的阳性率分别为３５．００％和４４．１２％，均明于高于高分化星形细胞瘤（４．３５％和６．５２％）；突变型ｐ５３蛋白染色阴性的星形细     

星形细胞肿瘤中MDM2蛋白与突变型p53蛋白的表达及其相关性研究

目的：探讨ｍｄｍ－２基因表达和ｐ５３基因突变在星形细胞肿瘤发生发展中的作用及两者的相关性。方法：采用ＳＡＢＣ免疫组化法对１２０例星形细胞肿瘤进行检测。结果：在分化不良性星形细胞瘤及多形性胶质母细胞瘤中，ＭＤＭ２蛋白的阳性率分别为３０．００％和３５．２９％，突变型ｐ５３蛋白的阳性率分别为３５．００％和４４．１２％，均明显高于高分化星形细胞瘤（４．３５％和６．５２％）；突变型ｐ５３蛋白染色阴性的星形细胞肿瘤中，ＭＤＭ２蛋白阳性率（２６．１５％）明显高于其染色阳性的肿瘤（９．３８％）。结论：ＭＤＭ２蛋白及突变型ｐ５３蛋白在星形细胞肿瘤中的表达均与该肿瘤的分化程度有关；ｍｄｍ－２基因扩增及产物ＭＤＭ２蛋白过度表达，可能是突变型ｐ５３蛋白染色阴性的星形细胞肿瘤发生的分子基础     

星形细胞瘤p16与Rb蛋白的表达及其相关性研究

目的检测ｐ１６与Ｒｂ蛋白在原发性星形细胞瘤中的存在状况，以探讨不同病理类型星形细胞瘤中ｐ１６与Ｒｂ蛋白表达及其相关性。方法使用抗ｐ１６及Ｒｂ蛋白抗体对１０２例星形细胞瘤手术标本进行免疫细胞化学检测。结果低度恶性星形细胞瘤（ＷＨＯⅠ～Ⅱ级）中ｐ１６及Ｒｂ蛋白均为阳性表达，在高度恶性星形细胞瘤（ＷＨＯⅢ～Ⅳ级）中其阳性表达分别为４８．１％（２６／５４）和５７．４％（３１／５４）。在３１例Ｒｂ蛋白阳性标本中，有２４例（７７．４％）显示ｐ１６蛋白表达缺失或低表达，而在２３例Ｒｂ蛋白阴性标本中却有１９例（８２．６％）显示ｐ１６蛋白阳性或强阳性。结论（１）ｐ１６及Ｒｂ蛋白参与星形细胞瘤细胞增殖过程并影响其细胞分化；（２）ｐ１６与Ｒｂ蛋白之间阳性表达的相互抑制，可能是高度恶性星形细胞瘤的标志之一。     

乳腺病变细胞核仁组成区嗜银蛋白与血清晨粘蛋白关系的研究

本文对２０例乳腺浸润性导管癌，２５例乳腺纤维腺瘤，３０例乳腺小叶增生的病理组织细胞进行图像分析，主要定量测定核仁组成区嗜银蛋白（ＡｇＮＯＲｓ）颗粒的数目、面积和核面积；再利用Ｐ５３、Ｃ－Ｎｅｕ单抗进行组织细胞的免疫组化测定，同时用ＥＬＩＳＡ方法测定患者外周血清层粘蛋白（ｌａｍｉｎｉｎ，ＬＮ）。结果发现：在病变细胞内，ＡｇＮＯＲｓ颗粒面积和核面积的比值不但在各病变组与正常乳腺组织有显著性差异（Ｐ＜０．０５），而且与Ｐ５３、Ｃ－Ｎｅｕ之间也有一定相关性，随着肿瘤的恶化和浸润程度的改变，细胞外间质物质之一的层粘蛋白的含量也会有一定范围的变化，提示肿瘤细胞内蛋白异常增殖，ＡｇＮＯＲｓ颗粒变化不但与细胞基因调控失常有关，也直接影响细胞外间质ＬＮ的含量变化，使得血清中ＬＮ含量增高。从而发现细胞内ＡｇＮＯＲｓ颗粒数和血清ＬＮ二者之间存在一定的相关性（ｒ＝０．９２）。这将为乳腺细胞的病变、恶化、浸润的实验诊断提供了一定的依据。     

星形细胞肿瘤p53蛋白和PCNA免疫组化及其临床病理意义

应用免疫组化和图象分析技术对人脑星形细胞肿瘤中抑癌基因ｐ５３蛋白（４７例）和增殖细胞核抗原（ＰＣＮＡ）（９７例）的定位、分布及反应强度与分级和预后的关系进行了研究。结果显示；３种ｐ５３蛋白抗体的阳性率为２３．４％～６６．７％，其中ＣＭ－１抗体阳性率高于ｐＡｂ１８０１和ｐＡｂ２４０；ｐ５３表达水平在Ⅱ～Ⅳ级高于１级，并与ＰＣＮＡ标记指数之间相关。ＰＣＮＡ反应强度既与分级相关，又与预后相关，对于分析星形细胞瘤增殖活性和恶性程度有重要意义。     

乳腺病变细胞核仁组成区嗜银蛋白与血清层粘蛋白关系的研究

本文对２０例乳腺浸润性导管癌，２５例乳腺纤维腺瘤，３０例乳腺小叶增生的病理组织细胞进行图像分析，主要定量测定核仁组成区嗜银蛋白（ＡｇＮＯＲｓ）颗粒的数目、面积的核面积；再利用Ｐ５３、Ｃ－Ｎｅｕ单抗进行组织细胞的免疫组化测定，同时用ＥＬＩＳＡ方法测定患者外周血清层粘蛋白（ＬＮ）。结果发现：在病变细胞内，ＡｇＮＯＲｓ颗粒面积和核面积的比值不但在各病变组与正常乳腺组织有显著性差异（Ｐ〈０．０５），而且与     

AgNOR在骨巨细胞瘤分级及预后判定中的价值

对４２例骨巨细胞瘤（ＧＣＴ）患者进行ＡｇＮＯＲ计数，其中Ｉ级１８例，Ⅱ级１４例，Ⅲ级１０例，结果发现ＡｇＮＯＲ在Ｉ级与Ⅱ级瘤间差异无显著性（Ｐ〉０．０５）而在Ⅱ级与Ⅲ级瘤间差异有高度显著性（Ｐ〈０．０１）。提示ＡｇＮＯＲ的表达与Ｊａｆｆｅ分级不太一致，因而，我们倾向于将骨ＧＣＴ只分为良，恶性两肿，而且ＡｇＮＯＲ的高低与骨ＧＣＴ的预后有关。     

AgNOR图像定量分析对肝针吸良恶细胞的诊断价值

目的：探讨ＡｇＮＯＲ图像定量分析对针吸肝细胞癌及增生肝细胞的鉴别诊断价值，方法：应用真彩色图像分析技术对肝针吸细胞中的２０例肝癌及５例增生肝细胞核内ＡｇＮＯＲ进行了定量研究，结果：肝针吸癌细胞核内，ＡｇＮＯＲ平均面积，平均积分光密度，直径及平均颗粒数明显高于增生肝细胞（Ｐ〈０．０１），结论：ＡｇＮＯＲ图像定量分析可为肝针吸癌细胞和增生肝细胞的鉴别诊断提供一种新的定量指标，ＡｇＮＯＲ的形态，数量及分     

免疫组化和PCR—SSCP检测p53基因异常的一致性探讨

目的：探讨免疫组化检测ｐ５３蛋白表达和ＰＣＲ－ＳＳＣＰ检测ｐ５３基因突变的一致性。方法：单克隆抗体ＤＯ－７检测８５例非小细胞肺癌（ＮＳＣＬＣ）的ｐ５３蛋白表达，ＰＣＲ－ＳＳＣＰ检测其中３１例腺癌的ｐ５３基因突变。结果：８５例ＮＳＣＬＣ中ｐ５３蛋白表达阳性率为６８％（５８／８５），３１例腺癌中ｐ５３蛋白表达阳性率为６１％（１９／３１），１４例（４６％）出现ｐ５３基因５～８外显子突变，ｐ５３蛋白免疫组化和ＰＣＲ－ＳＳＣＰ检测ｐ５３基因突变无显著相关（χ２＝０．１，Ｐ＝０．７６），其一致率为５２％。结论：ｐ５３蛋白表达并不能很好地反映ｐ５３基因突变。     

Loss of DCC expression in astrocytomas: relation to p53 abnormalities, cell kinetics, and survival

AIMS: Although frequent reduction or loss of DCC (deleted in colorectal carcinomas) has been demonstrated in gliomas, the association with cell kinetics and survival is still unclear. METHODS: A total of 119 astrocytomas, comprising 39 grade IV, 36 grade III, and 44 low grade tumours, were immunohistochemically investigated, along with 26 normal adult brain samples and two fetal brains. The results were compared with p53 abnormalities, Ki-67 labelling index (LI), mitotic index (MI), apoptotic index (AI), and survival. RESULTS: In normal adult and fetal brain tissues, DCC expression was detected in mature and terminally differentiated neuronal cells but not glial elements. In astrocytomas, whereas DCC expression was still clearly shown with low grade malignancy, DCC scores were significantly decreased in high histological grade malignancy, along with an increase in cell kinetics determined by AI, MI, and Ki-67 LI values. In addition, p53 LI values were significantly increased, although a direct link between DCC scores and p53 LI values was not evident. Univariate analysis revealed that high DCC scores and low p53 LI values were closely related to a favourable outcome for astrocytoma, although only the AI was an independent prognostic factor. CONCLUSIONS: The loss of DCC expression may be closely related to changes in cell kinetics and tumour phenotype in astrocytomas, independent of p53 abnormalities.     

胰腺癌P53蛋白表达与AgNORs量及组织学分级的关系

目的：研究胰腺癌P53蛋白表达与癌细胞核仁组成区嗜银蛋白（AgNORs）量及组织学分级的关系。方法：用免疫组织化学法检测56例胰腺癌组织及25例正常胰腺组织中突变型P53蛋白的表达； AgNORs染色技术检测胰腺癌细胞的AgNORs含量；观察肿瘤的组织学分级。结果： 56例胰腺癌中P53蛋白表达阳性28例（50％），正常胰腺细胞均为阴性，P53蛋白在胰腺癌组织和正常胰腺组织中的表达有显著差异(P<0.01)。28例P53蛋白阳性的胰腺癌组织，AgNORs计数为9.14±2.08；28例P53蛋白阴性的胰腺癌中，AgNORs计数为5.99±1.84，二者有显著差异（P<0.01）。P53蛋白表达与肿瘤组织学分级呈显著负相关。不同的组织学分级之间，AgNORs计数有显著差异（P<0.01）。结论：胰腺癌发生发展的过程包含了〖STBX〗p53〖STBZ〗基因的突变。P53蛋白表达和AgNORs含量可反映胰腺癌的恶性程度，是一个有效的判断胰腺癌预后的指标。     

Caveolin-1 expression in diffuse gliomas: correlation with the proliferation index, epidermal growth factor receptor, p53, and 1p/19q status

Caveolin-1 (cav-1) has been proposed as an immunohistochemical marker able to distinguish astroglial from oligodendroglial tumors. In addition, it has been suggested that the reduction of caveolin-1 expression in glioblastoma cells increases their proliferative and invasive potential. Accordingly, the present study investigates caveolin-1 immunoexpression and correlation with the 1p/19q status, histologic grade, proliferation index, epidermal growth factor receptor, and p53 expression in a series of 73 diffuse gliomas. A membranous and cytoplasmic immunolabeling for caveolin-1 was detected in neoplastic cells of 60% of cases. No significant differences in terms of caveolin-1 expression were observed between astrocytomas, oligodendrogliomas, and oligoastrocytomas. In addition, caveolin-1 expression was not correlated with 1p/19q status in oligodendrogliomas and mixed oligoastrocytomas. Caveolin-1 was expressed in most high-grade (World Health Organization III and IV) gliomas. Low caveolin-1 expression correlated with a higher Ki-67 labeling index and the absence of p53 overexpression in glioblastomas, and it was significantly associated with epidermal growth factor receptor overexpression in anaplastic astrocytomas. In conclusion, the present study indicates that caveolin-1 is not useful as diagnostic marker to differentiate grade II astrocytomas from oligodendrogliomas.     

Analysis of 2 antiapoptotic factors in gliomas: bcl-2 overexpression and p53 mutations

BACKGROUND: p53 mutations and immunoreactivity have been described in human gliomas. During the past few years, some authors have found bcl-2 overexpression in astrocytomas, although their correlation with histological grade is a matter of disagreement. A relation between bcl-2 overexpression and p53 immunoreactivity has also been suggested. OBJECTIVES: To analyze the frequency of presentation of bcl-2 and p53, their clinicopathologic implications, and their possible coexpression. METHODS: We studied p53 and bcl-2 with immunohistochemical and molecular methods in 61 gliomas (including 21 astrocytomas, 9 anaplastic astrocytomas, 29 glioblastomas, 1 oligodendroglioma, and 1 mixed glioma). RESULTS: We discovered a high level of bcl-2 overexpression (57%). Overexpression of bcl-2 can be an early event in gliomas tumorigenesis, although no correlation was found with any of the clinicopathologic parameters studied. p53 mutations were present in a small proportion of gliomas (17%). p53 immunoreactivity was present in 34 cases (57%), and it was related to histological grade and a supratentorial location. A high percentage of tumors (26 cases, 42%) presented p53 immunoreactivity without p53 mutations. CONCLUSIONS: Since there was no relation between bcl-2 overexpression and p53 mutations or p53 immunoreactivity, both factors may not act together in the genesis and evolution of gliomas.     

Expression of p27KIP1 in human gliomas: relationship between tumor grade,proliferation index,and patient survival

Numerous studies examining the prognostic significance of p27KIP1 expression in human cancer have shown that decreased expression often is an independent prognostic factor associated with worse survival. However, the prognostic value of p27KIP1 expression in gliomas is less well established. To further address this issue, we evaluated the relationship between p27KIP1 protein expression in a series of 50 astrocytomas with clinicopathologic parameters including age, tumor grade, MIB-1 proliferation index, and patient survival using both Western blot analysis and immunohistochemistry. The level of p27KIP1 protein expression in 9 nonneoplastic brain tissue specimens served as a control. Sixteen high-grade astrocytomas were analyzed by Western blot, and 26 high-grade astrocytomas were analyzed by immunohistochemistry for levels of p27KIP1 protein expression. Regardless of the technique used to measure p27KIP1, approximately 50% of the high-grade tumors were low expressors and the other 50% were high expressors. Thus, expression of p27KIP1 was independent of tumor grade. Loss of p27KIP1 expression is often associated with an increase in proliferative activity. We measured the rate of tumor cell proliferation using MIB-1 immunostaining in 16 high-grade astrocytomas to determine whether there was an inverse correlation between p27KIP1 expression and proliferation. No correlation between p27KIP1 expression and MIB-1 labeling index or patient survival was found. Using immunohistochemistry, we noted that the staining pattern of p27KIP1 in glioblastomas was mainly in the pseudopalisading cells that outline areas of necrosis. Because p27KIP1 can be up-regulated by hypoxia, this staining pattern would be consistent with our observation that hypoxia-inducible factor 1alpha is expressed primarily in pseudopalisading tumor cells around necrotic zones. It has been shown that a high level of p27KIP1 prevents apoptosis in hypoxic cells. Thus, maintenance of high levels of p27KIP1 in gliomas could result from the hypoxic microenvironment present within the tumor. No correlation was found between p27KIP1 expression and any of the clinicopathologic parameters tested, including patient age and tumor grade, the 2 strongest predictors of survival among glioma patients.     

Flow cytometric DNA and nuclear antigen content in astrocytic neoplasms

Simultaneous flow cytometric DNA content and proliferation-associated nuclear antigen (p105) quantitation was performed on 23 astrocytic tumors and the results correlated with histologic subtype. Three of nine anaplastic astrocytomas and one of ten glioblastomas had an identifiable aneuploid peak, while all four well differentiated astrocytomas were diploid. Cell cycle analysis of malignant gliomas revealed a higher mean percentage of S and G2M cells compared to well differentiated astrocytomas but there was considerable overlap between histologic subtypes. Nuclear antigen analysis of diploid tumors showed a higher mean p105 fluorescence of S + G2M cells than G0G1 cells from the same case but there were no apparent differences in p105 expression by histologic subtype. Aneuploid tumors showed enhanced expression of p105 relative to diploid cells. The findings suggest that the aggressive course of high grade glial tumors may be related to an abnormal DNA stemline or an increase in proliferative activity.     

An experimental model for anaplastic astrocytomas and glioblastomas using adult F344 rats and N-methyl-N-nitrosourea

An experimental model for induction of gliomas corresponding to human anaplastic astrocytomas and glioblastomas is reported. Eleven week old F344 and ACI rats were given 100 or 200 p.p.m. N-methyl-N-nitrosourea (MNU) solution as their drinking water for 42 weeks. Gliomas were induced at very high incidences (82.5-92.5%) in each group. Induced gliomas showed apparent evidence of morphologic malignancy by an analysis based on diagnostic criteria of human astrocytomas. All of the gliomas from the killed animals were classified histologically into subtypes according to the classification scheme used in the diagnosis of human gliomas. The majority of macrotumors more than 1 mm in diameter in both strains were diagnosed as anaplastic astrocytomas and glioblastomas. lmmunohistochemically, tumor cells in these tumors were almost negative for glial fibrillary acidic protein, while ultrastructurally neoplastic astrocytes contained glial filaments. A strain difference was observed in the ratio of histological subtypes of macrotumors. In F344 rats, astrocytic tumors diagnosed as anaplastic astrocytomas and glioblastomas of an astrocytic type formed the majority, whereas glioblastomas of mixed oligo-astrocytic type predominated in ACI rats. The results indicate that MNU-administration to adult F344 rats may provide a suitable experimental model for gliomas which occur in adult humans.     

胶质瘤增殖活性和肿瘤基因蛋白表达及其意义

目的探讨胶质瘤增殖活性和肿瘤基因蛋白表达与分化和预后间的关系。方法应用免疫组化和图像分析技术对１２４例脑胶质瘤增殖细胞核抗原（ＰＣＮＡ）和几种肿瘤基因蛋白进行定性、定量研究。结果ＰＣＮＡ反应强度与级别和预后显著相关;ｃ－ｅｒｂＢ－２蛋白表达在分化程度高的胶质瘤强于分化程度低者,存活５年以上的病例阳性强于存活５年以下者。ＥＧＦ（４０．０％）、ＥＧＦＲ（９１．４％）和ｐ２１ｒａｓ（５３．３％）与分级和预后无显著关系。３种ｐ５３蛋白抗体阳性率均以Ⅱ～Ⅳ级胶质瘤为高;ｐ５３与ＰＣＮＡ反应强度平行。结论ｐ２１ｒａｓ、ｃ－ｅｒｂＢ－２、ＥＧＦ和ＥＧＦＲ改变在胶质瘤发生、发展过程中可能是早期事件,恶变后不再随级别增加而加重,而ｐ５３基因突变涉及胶质瘤发展各个阶段;ＰＣＮＡ能较好地反映胶质瘤的恶性程度。     

IDH1R132H在中枢神经系统胶质瘤中的表达及其鉴别诊断意义

目的 探讨异柠檬酸盐脱氢酶1基因(isocitrate dehydrogenase 1 gene,IDH1)突变的表达产物IDH1R132H在人中枢神经系统胶质瘤中的表达及其在鉴别诊断中的意义.方法 应用免疫组织化学EnVision法检测不同级别胶质瘤75例(包括WHOⅡ级33例,Ⅲ级20例和Ⅳ级22例)与各种原因造成的胶质增生性脑组织中IDH1R132H的表达情况,并与p53的表达情况进行比较分析.结果 IDH1R132H在WHOⅡ级、Ⅲ级和Ⅳ级胶质瘤的表达阳性率分别为57.6%(19/33)、40.0%(8/20)和27.3%(6/22),差异有统计学意义(P=0.024).IDH1R132H的具体表达部位在胶质瘤细胞的胞质、突起以及部分细胞核.除肿瘤主体部分密集增生的肿瘤细胞呈阳性表达以外,包括皮质和白质在内的肿瘤周边区域单个或散在的肿瘤细胞也呈强阳性表达.IDH1R132H阳性病例有额叶受累为主的倾向.胶质增生组织、毛细胞型星形细胞瘤均为阴性表达.另外,p53在WHOⅡ级、Ⅲ级和Ⅳ级胶质瘤的表达阳性率分别为42.4%(14/33)、65.0%(13/20)和77.3%(17/22).IDH1R132H的表达与p53的表达之间没有明确的相关性(P=0.766).结论 IDH1R132H在各级别胶质瘤中均有表达,且随着肿瘤级别的增高呈表达下降趋势.IDH1R132H可以作为鉴别低级别胶质瘤和胶质增生性病变的一个有用的分子标志物.

Abstract：

Objective To investigate the immunohistochemical expression of isocitrate dehydrogenase 1 gene ( IDH1 ) R132H in glioma and its diagnostic utility. Methods Immunohistochemical study of IDH1R132H expression was performed on formalin-fixed paraffin-embedded tissue samples of 75 gliomas, including 33 cases of grade Ⅱ , 20 cases of grade Ⅲ and 22 cases of grade Ⅳ tumors. Six cases of pilocytic astrocytoma and 12 cases of gliosis were used as controls. Results Nineteen in 33 cases of grade Ⅱ (57.6%), 8 in 20 cases of grade Ⅲ (40. 0% ), 6 in 22 cases of grade Ⅳ (27. 3% ) showed positive cytoplasmic staining of IDH1R132H. Scattered invasive glioma cells at the tumor periphery also expressed IDH1R132H. Gliomas involving the frontal lobe showed more strong IDH1R132H staining. In contrast, none of the pilocytic astrocytomas and gliosis showed IDH1R132H staining. Moreover, the rate of p53 immunopositivities were 42. 4% ( 14/33 ) in grade Ⅱ , 65.0% (13/20) in grade Ⅲ and 77.3% (17/22) in grade Ⅳ gliomas. There were no statistic correlations between expression of IDH1R132H and p53.Conclusion IDH1R132H tends to express preferentially in low-grade gliomas, and it thus may serve as a valuable marker in distinguishing low grade gliomas from gliosis.     

Antigenic staining patterns of human glioma cultures: primary cultures, long-term cultures and cell lines

Summary The immunocytochemical staining patterns of cultured glioma cells were investigated. Fifty nine individual cases were stained at differentin vitro ages for glial fibrillary acidic protein, fibronectin, galactocerebroside, HNK-1/Leu 7, A2B5, vimentin, factor VIII and A4. Histologically, the cases were composed of eight low-grade astrocytomas, 11 high-grade astrocytomas, four low-grade oligodendrogliomas, seven high-grade oligodendrogliomas and 29 glioblastomas. The 45 cases were analysed within the first 3 weeks of culture, many of them as primary cultures. In 11 cases stainings were performed repeatedly at intervals of up to 6 months.Glial fibrillary acidic protein staining was positive in most of the early cultures of astrocytomas (low and high grade) and glioblastomas; expression in more than 50% of the cells was found in 1 of 5 low-grade astrocytomas, 5 of 11 high-grade astrocytomas and 14 of 29 glioblastomas. Two of the high-grade astrocytomas were stained once more after 6 weeks in culture and were found to be only 1% positive for glial fibrillary acidic protein but strongly positive for fibronectin. The same was true for five of the glioblastoma cases. Two of these cases remained glial fibrillary acid protein positive and developed into stable permanent cell lines. Only one case started with 1% of glial fibrillary acidic protein positive cells and later developed into a 99% glial fibrillary acidic protein positive cell line. Neither HNK-1/Leu 7 expression nor A2B5 staining appeared to have a relationship to the glial fibrillary acidic protein staining. It was observed that glial fibrillary acidic protein and HNK-1/Leu 7 were both 100% in some cases but that later one of the two antigens disappeared but not the other. The amount of glial fibrillary acidic protein staining does not allow the prediction of A2B5 staining.The study shows that initiation of primary cultures on an extracellular matrix yields more glial fibrillary acidic protein positive cells in primary cultures than have been found in other studies. It is concluded that only a rigid standardization of culture conditions will ensure the validity of comparisons ofin vitro data obtained in primary cultures.