胃肠道和胃肠道外间质瘤临床病理分析

目的 探讨胃肠道间质瘤(GIST)与胃肠道外间质瘤(EGIST)的临床病理学特点和免疫组织化学表达特征.方法对48例GIST和6例EGIST作了临床病理形态学观察和免疫组化分析.同时观察8例胃肠道平滑肌瘤,作对比分析.结果 48例GIST和6例EGIST CD117阳性率均为100%,CD34阳性率均为83.3%.8例胃肠道平滑肌瘤,CD117和CD34均为阴性,desmin和SMA均呈弥漫强阳性表达.结论 CD117和CD34标记阳性是确定间质瘤最具有诊断价值的依据.但不能作为良恶性判断指标.     

68例胃肠道及腹腔间质瘤临床病理及免疫组织化学研究

目的 探讨胃肠道及胃肠道外间质瘤的临床病理组织形态学和免疫组织化学特点及良恶性诊断标准和鉴别诊断.方法 用CD117和CD34等抗体,通过免疫组化S-P法对发生于胃肠道、腹腔内的间叶源性肿瘤进行研究,确诊68例间质瘤.对其进行临床病理组织学和免疫组化分析.结果 按肿瘤发病部位分为胃肠道间质瘤(GIST)组和胃肠道外GIST型组.GIST组54例CD117阳性表达率为92.6%,CD34的阳性表达率为77.8%;胃肠道外GIST型组14例CD117阳性表达率为85.7%,CD34阳性表达率为71.4%;Actin与S-100阳性瘤细胞大部分为散在或小灶状分布,Dcsmin均为阴性表达.结论 免疫组化CD117和CD34阳性表达是确诊间质瘤最有诊断价值的依据,间质瘤良、恶性诊断上仍需结合肿瘤的大体、组织学形态及生物学行为等综合考虑.     

子宫肉瘤c-kit表达意义的探讨

目的:探讨胃肠道外间质肿瘤-子宫肉瘤32例(平滑肌肉瘤20例、子宫内膜间质肉瘤10例及子宫腺肉瘤2例),测定酪氨酸激酶(c-kit CD117)的阳性表达率,是否亦具备类同胃肠道间质肿瘤细胞中的所含有c-kit促使CD117呈阳性,以便寻找治疗子宫肉瘤的新途径.方法:对32例子宫肉瘤,均以免疫组化测定CD117,并选用经病理确诊及阳性表达CD117的胃肠道间质肿瘤5例为对照.结果:子宫肉瘤测定CD117阳性率依次为:子宫平滑肌肉瘤11/20例(55%)、子宫内膜间质肉瘤3/10例(30%)及子宫腺肉瘤0/2例.结论:对阳性表达CD117不可切除或转移性子宫肉瘤患者选择分子靶向治疗,提供理论依据.     

CD117在胃肠道间质瘤中的表达及意义

目的探讨CD117在胃肠道间质瘤中的表达及其意义。方法应用免疫组织化学方法检测100例胃肠道间质瘤组织CD117的表达。结果 100例胃肠道间质瘤组织中,CD117阳性表达率为96.0%（96/100）,其中胃阳性率为96.9%（63/65）,小肠阳性率为96.4%（27/28）,腹膜后阳性率为85.7%（6/7）;良性间质瘤阳性率为96.4%（80/83）,交界性阳性率为91.7%（11/12）,恶性阳性率为100.0%（5/5）,CD117表达在不同部位间及不同生物学行为间差异均无统计学意义（P〉0.05）。结论 CD117是诊断胃肠道间质瘤特异性较高的抗体,在与胃肠道平滑肌肿瘤、雪旺氏肿瘤的鉴别诊断上也具有较高的价值;CD117的表达与间质瘤分布部位及良、恶性无关,不能作为分化程度的指标。     

抑制Src酪氨酸激酶对非小细胞肺癌细胞VEGF表达的影响

目的:探讨抑制Src酪氨酸激酶对非小细胞肺癌细胞VEGF表达的影响。方法:采用ELISA法检测非小细胞肺癌细胞株培养上清中VEGF表达以及抑制Src酪氨酸激酶对VEGF表达的影响;采用雄性严重联合免疫缺陷(SCID)小鼠,敲除NK细胞,建立非小细胞肺癌细胞诱导的皮下肿瘤和实验性肺转移瘤动物模型,采用免疫组化法研究抑制Src酪氨酸激酶对皮下肿瘤和肺转移瘤中VEGF表达的影响。结果:本实验采用的3种非小细胞肺癌细胞都表达VEGF。0.1μmol/L、0.3μmol/L、1μmol/L和3μmol/L Src酪氨酸激酶抑制剂对H226细胞VEGF表达的抑制率分别为18%、8%、24%和47%,对A549细胞VEGF表达的抑制率分别为14%、23%、50%和43%,对PC-9细胞VEGF表达的抑制率分别为25%、56%、51%和71%。抑制Src酪氨酸激酶明显抑制VEGF在肺转移瘤和皮下肿瘤中的表达。结论:抑制Src酪氨酸激酶能够抑制非小细胞肺癌细胞体外和体内VEGF的表达。     

成人急性白血病中CD117与CD34共表达的临床意义

背景与目的:c-kit受体(c-kitreceptor,c-kitR,CD117)是干细胞因子受体。CD117在急性非淋巴细胞白血病(acutenon-lymphoblasticleukemia,ANLL)中高表达,可作为髓系免疫学标记物,对诊断ANLL有一定参考价值。但是,CD117也可在部分急性淋巴细胞白血病(acutelymphoblasticleukemia,ALL)中表达。CD34为造血干(祖)细胞抗原标记物,在ANLL和ALL中均有高表达。本研究旨在探讨CD117和CD34在急性白血病中共表达的临床意义。方法:采用流式细胞术(flowcytometery,FCM)分别检测92例ALL和81例ANLL初诊患者骨髓单个核细胞(BMMNC)CD117的阳性率和阳性细胞水平;比较ALL和ANLL患者CD117/CD34共表达率的差异,并比较ALL患者中CD117和CD117/CD34共表达率的差异。设立20例健康成人为对照组。结果:在ALL和ANLL患者中CD117阳性率分别为15.2%和71.6%,CD117/CD34共表达率分别为5.4%和55.5%,差异有显著性(P<0.001)。ALL患者中CD117表达率和CD117/CD34共表达率分别为15.2%和5.4%,差异有显著性(P=0.029)。结论:CD117可作为急性白血病的MIC分型诊断之髓系免疫学标志,用以协助ANLL的临床诊断;较之CD117表达,CD117/CD34在ALL中的共表达率更低,可籍此协助排除ALL。     

胃肠道间质瘤的免疫组化观察与临床病理意义的研究

目的:探讨胃肠道间质瘤(GIST)的临床病理特点以及CD117、CD34、Desmin、DOG-1、S-100、SMA的表达情况,并分析两者之间的关系。方法:用免疫组化SP法检测62例胃肠道间质瘤组织中CD117、CD34、DOG-1、S-100、SMA的表达情况,分析其与临床病理因素(性别、年龄、生长部位、肿瘤大小、核分裂相、组织学类型)的相关性。结果:62例GIST中极低度危险度13例,低度危险度17例,中度危险度13例,高度危险度19例。62例GIST中CD117阳性(93.55%,58/62),CD34阳性(82.26%,51/62),DOG-1阳性(90.32%,56/62),Desmin阳性(3.23%,2/62),SMA阳性(41.93%,26/62),S-100阳性(19.35%,12/62)。CD34的表达与肿瘤大小以及危险度有关。与DOG-1+/CD117+相比,另外两组(DOG-1+/CD34+,CD117+/CD34+)的共同阳性表达率明显降低。在GIST中,与DOG-1相比,CD117在GISTs的阳性率表达中,没有显著的统计学差异,而CD34则存在统计学差异。结论:DOG-1作为GIST的标志物,在诊断GIST方面,与CD117同样具有较好的特异性和敏感性。同时,CD117、CD34及DOG-1这三个指标对于GISTs的正确诊断以及之后的病人的个体化治疗有着指导意义。     

24例胃肠间质瘤病理及免疫组化分析

 目的　探讨胃肠间质瘤病理诊断及免疫组化特点。方法　对 2 4例胃肠间质瘤进行常规病理及免疫组化CD117、CD34、SMA、S 10 0染色特点分析。结果　 2 4例胃肠间质瘤由梭形细胞和上皮样细胞组成 ,其中 2 1例CD117和 18例CD34标记阳性 ,阳性表达率分别为 87.5 %和 75 %。结论　胃肠间质瘤是胃肠常见的间叶性肿瘤 ,缺乏定向分化。CD117和CD34标记阳性对胃肠间质瘤的诊断具有非常重要的价值     

75例胃肠间质瘤临床病理分析

对75例胃肠间质瘤（GIST）进行常规病理及免疫组化CD117、CD34、SNA、S-100、Ki-67等染色特点分析,胃肠间质瘤由梭形细胞和上皮样细胞组成．其中66例CD117和56例CD34标记阳性,阳性表达率分别为88％和74．7％。胃肠间质瘤缺乏定向分化．CD117和CD34标记阳性对胃肠间质瘸的诊断具有重要价值．检测Ki-67对预测GIST恶性潜能非常有用,Ki-67标记阳性病例更具有复发的倾向。     

骨髓增生异常综合征患者骨髓单个核细胞CD34、CD117的表达及其临床意义

 目的　探讨骨髓增生异常综合征（MDS）患者骨髓单个核细胞CD34、CD117的表达及临床意义。方法　采用直接免疫荧光标记法标记细胞表面分化抗原,流式细胞术测定,对37例MDS患者的骨髓单个核细胞CD34、CD117表达及临床意义进行分析。依据MDS的WHO分型方案、染色体核型以及国际预后积分系统（IPSS）将MDS患者划分为RA-RARS-RCMD 组、RAEBⅠ-RAEBⅡ组;染色体良好组、染色体不良组;中危Ⅰ组、中危Ⅱ组、高危组。结果　RA-RARS-RCMD组19例中11例CD34、CD117表达阳性,RAEBⅠ-RAEBⅡ组18例患者CD34、CD117表达均阳性;随着疾病恶性程度的增高,CD34、CD117表达明显升高;染色体良好组22例中14例患者CD34、CD117表达阳性,染色体不良组15例患者均表达CD34、CD117;随着异常克隆的出现,CD34、CD117表达升高;中危Ⅰ组17例中9例CD34、CD117表达阳性;中危Ⅱ组11例、高危组9例,所有患者CD34、CD117表达均阳性;随着预后积分的递增,CD34、CD117表达随之升高。结论　CD34、CD117检测有助于MDS 的分型、预后判断。     

C-kit receptor (CD117) expression on plasma cells in monoclonal gammopathies

The surface expression of CD117 antigen (c-kit) on plasma cells from 158 multiple myeloma (MM), 12 plasma cell leukemia (PCL), 7 MGUS, 7 IgM lymphoplasmacytic lymphoma patients and 10 healthy subjects has been analyzed by flow cytometry using triple staining with the monoclonal antibodies CD138, CD117 and CD38. The antigen expression intensity was calculated as relative fluorescence intensity (RFI) and for direct quantitative analysis the QuantiBRITE test (Becton Dickinson) was applied. Antibody bounding capacity (ABC) was calculated using QuantiCALC software. CD117 antigen was present in 49/158 MM, 5/12 PCL and 5/7 MGUS patients. The RFI values ranged from 0.2 to 20.2 in particular MM patients (mean: 11.0 ± 5.3; median 11.5) while the number of CD117 binding sites (ABC) on MM plasma cells ranged from 637 to 6217 (mean: 3029 ± 1568; median 2946) (r = 0.8328). In responsive to chemotherapy c-kit positive MM patients the percentage of CD117⁺ plasma cells in the bone marrow decreased significantly while in c-kit negative MM patients the percentage of CD117⁺ cells in bone marrow did not change and remained in the normal limits. When comparing the clinical and biological disease characteristics (monoclonal protein isotype, albumin, β₂-microglobulin, lactate dehydrogenase, stage of disease, response to chemotherapy, survival time) of c-kit positive and c-kit negative cases, no significant differences were found. In CD117 positive PCL cases expression of CD117 was detected in bone marrow plasma cells as well as in peripheral blood plasma cells. Normal plasma cells and those in IgM lymphoplasmacytic lymphoma did not show reactivity for the CD117 antigen. We conclude that it may be rationale to consider usefulness of therapy with tyrosine kinase inhibitors in the management of c-kit positive plasma cell proliferations. In one third of MM and PCL patients c-kit antigen could be considered as a "tumor associated marker" and together with CD38 and CD138 it may be of value for the identification of the malignant clone in minimal residual disease as it was first suggested by Spanish authors.     

Clinicopathological correlates of plasma cell CD56 (NCAM) expression in multiple myeloma

The aim of this prospective, long-term study was to define the flow cytometric characteristics of plasma cell CD56 expression as well as determine the clinical characteristics of 204 multiple myeloma (MM) patients and 26 plasma cell leukemia (PCL) patients with regard to CD56 expression. CD56 expression intensity was determined by measurement of antigen molecules on the cell defined as Antibodies Bound per Cell (ABC) and calculation of Relative Fluorescence Intensity (RFI). CD56 expression was found in 66% of MM and 54% of PCL cases. The RFI values for individual MM patients ranged from 7.6 to 27.4 while ABC values on MM plasma cells from 2255 to 58469. There was a correlation between the proportion of all bone marrow CD38⁺⁺/CD138⁺ cells with CD56 expression and ABC and RFI indices. With regard to CD56 expression positive patients, the CD56^- MM patients presented lower frequency of osteolysis (p = 0.01). The median survival was 48 months in CD56⁺ patients and 43 months (p = 0.84) in CD56^- cases. In conclusion, CD56 expression carries no distinct adverse prognosis and the lack of CD56 expression does not define a unique clinicopathological or prognostic entity in MM. A remarkable heterogeneity of CD56 expression intensity in CD56⁺ patients imposes the necessity of determining CD56 expression intensity in candidates to antibody-based therapy.     

CD117 (c-kit) is aberrantly expressed in a subset of MGUS and multiple myeloma with unexpectedly good prognosis

CD117 (c-kit) was evaluated on normal plasma cells (PC) (n=10), PC of individuals with monoclonal gammopathy of undetermined significance (MGUS, n=12), malignant PC from patients with multiple myeloma (MM) either at diagnosis (n=83) or relapse (n=38) and on 23 human myeloma cell lines (HMCL). Whereas CD117 is never expressed in normal PC, it is expressed in 50% of MGUS (p=0.015). Furthermore, 33% of MM at diagnosis do express CD117, as opposed to 8% of those in relapse (p=0.003). Finally, CD117 was never found in HMCL. CD117 expression was associated with a better prognosis: overall survival was 93% at 4 years in CD117+ MM versus 64% in CD117- MM (p=0.05). Conversely, lack of CD117, but also high beta-2 microglobulin, t(4;14) and CD221 (IGF-1R) expression were associated with a poorer prognosis. Multivariate analysis revealed that CD117- patients were those with CD221 and t(4;14) and had the poorest prognosis. In conclusion, CD117 (c-kit) is aberrantly expressed on a subset of MGUS and MM with a more indolent presentation and is functionally antinomic to CD221 (IGF-1R). CD117 expression could be related to a specific oncogenic pathway in MM.     

Immunohistochemical identification of HER-2/neu overexpression and CD117 (c-kit) expression in multiple myeloma

Multiple myeloma (MM) is the most common plasma cell dyscrasia. Conventional therapy results in a median survival of 3-5 years. Patients with B-cell disorders and coexistent HER-2/neu overexpression in solid tumors have a poorer prognosis than those without an underlying B-cell disorder. This, and the recent success of the tyrosine kinase inhibitor, imatinib mesylate in chronic myelogenous leukemia, led us to evaluate the incidence and role of c-kit (CD117) and HER-2/neu overexpression in MM. We conducted a retrospective study to determine the incidence of HER-2/neu and c-kit overexpression in MM. HER-2/neu overexpression was evaluated using the DAKO Hercep test and c-kit overexpression was assessed using conventional immunohistochemistry (IHC); 69 patients with a diagnosis of MM were identified, of whom, 31 patients (19 males and 12 females) had an adequate pathological specimen available for IHC testing; 4 out of 31 patients (12.9%) showed HER-2/neu overexpression, while 5/31 (16.13%) showed CD117 expression. Two patients (6.45%) showed both HER-2/neu and c-kit overexpression. Although both HER-2/neu and c-kit are not expressed very frequently in patients with MM, there appears to be a subgroup of patients in whom, either one or both these oncogenes is overexpressed. Given our small sample size, it is difficult to comment on the effect of CD117 and/or HER-2/neu overexpression on survival. Future larger studies are needed to define the association in MM and to determine if the presence of one (CD117 or HER-2/neu) has an effect on overexpression of the other oncoprotein. Furthermore, it would be beneficial to identify the molecular nature of the interplay between HER-2/neu and c-kit, if any. Target-directed signal transduction inhibition therapy using tyrosine kinase inhibitors, may be a distinct possibility in a select group of patients with MM.     

Prognostic relevance of CD56 expression in multiple myeloma: a study including 107 cases treated with high-dose melphalan-based chemotherapy and autologous stem cell transplant

CD56 is a neural adhesion molecule and expressed in 70-80% cases of multiple myeloma (MM). Lack of CD56 expression has shown to be a poor prognosis in MM patients treated with conventional chemotherapy, but its prognostic relevance in MM treated with high dose chemotherapy and autologous stem cell transplant (ASCT) is not known. CD56 expression was evaluated by immunohistochemistry on bone marrow paraffin embed specimens from 107 MM cases undergoing Melphalan-based high dose therapy and ASCT. CD56 was expressed by the myeloma cells in 71% of the patients. CD56 negative myeloma was associated with bone lesions ( p = 0.032), but there was no association with any other biological or genetic risk factors including deletions 13q, p53 and IgH translocations, as evaluated by fluorescence in situ hybridization (FISH). There was no significant difference between CD56 positive and CD56 negative myeloma for progression free or overall survival ( p = 0.28 and p = 0.67, respectively). In contrast to reports of CD56 in myeloma treated with conventional chemotherapy, CD56 negativity was not found to confer a poor prognosis in these patients, suggesting Melphalan-based high-dose chemotherapy and ASCT may overcome the adverse influence of CD56 negative myeloma.     

CD45 expression by bone marrow plasma cells in multiple myeloma: clinical and biological correlations.

Multiple myeloma (MM) is characterized by accumulation of clonal plasma cells (PCs). CD45, a key regulator of antigen-mediated signaling and activation in lymphocytes, is present in early stages of PCs development. We studied CD45 expression on MM PCs by flow cytometry, correlating it to important biological disease characteristics. Additionally, we examined the expression of various adhesion molecules on PCs. A total of 75 patients with untreated MM (29), relapsed MM (17), smoldering MM (12), and monoclonal gammopathy of undetermined significance (MGUS) (17) were studied. The proportion of PCs expressing CD45 was higher among those with early disease (MGUS or smoldering MM) compared to those with advanced disease (new or relapsed MM) (43 vs 22%; P=0.005). Among those with advanced disease, patients with bone lesions had a lower percentage of CD45-positive (CD45+) PCs; 14 vs 34% (P=0.02). Patients with high-grade angiogenesis had a lower percentage of CD45+ PCs; 13 vs 31% (P=0.03). The median overall survival for the CD45+ group (>20% PCs positive) was 39 vs 18 months for the CD45-negative (CD45-) group (P=0.07). The expression of CD138, CD56 and CD54 were higher among the CD45- PCs. This study demonstrates important biological correlates of CD45 expression on myeloma cells.     

多发性骨髓瘤患者浆细胞免疫表型特点及其临床意义研究

目的：观察多发性骨髓瘤（MM）患者骨髓中浆细胞免疫表型特点,及其与患者临床预后的相关性。方法：收集35例MM患者资料,骨髓涂片及切片分别经瑞氏-吉姆萨和HE染色后,观察分析骨髓细胞形态及病理学特点。同时,取患者骨髓或外周血分别进行流式细胞术检测及相关实验室检查。结果：MM患者骨髓浆细胞不仅数量明显增多,且形态明显异常,切片中浆细胞分布类型包括塞实型16例（45.71%）,结节型14例（40.00%）和间质型5例（14.29%）。MM患者中出现血清LDH、β2-MG、Cr和BUN等检测指标升高的比例分别占80%、85.71%、62.86%和60%。MM患者浆细胞CD38、CD138均呈阳性表达,CD56、CD200、CD117和CD28阳性患者比例分别为65.71%、94.29%、60%和54.29%,CD20、CD81、CD33、CD27及CD13阳性患者比例分别为37.14%、42.86%、28.57%、57.14%和34.29%,而CD19及CD45阳性患者比例分别为22.86%和31.42%,且Igκ或Igλ链表达缺失呈单克隆增生。其中CD27和CD28的表达情况与MM患者预后密切相关,浆细胞CD27表达缺失及CD28阳性表达的患者5年总生存率较低（P < 0.05）。结论：MM患者骨髓中浆细胞免疫表型明显异常,其中CD27和CD28的表达与患者病情进展和临床预后具有显著相关性,因此免疫表型检测在MM患者临床诊断、治疗监测中具有重要意义。     

多发性骨髓瘤患者浆细胞免疫表型特点及其临床意义研究

目的：观察多发性骨髓瘤（MM）患者骨髓中浆细胞免疫表型特点，及其与患者临床预后的相关性。方法：收集35例MM患者资料，骨髓涂片及切片分别经瑞氏-吉姆萨和HE染色后，观察分析骨髓细胞形态及病理学特点。同时，取患者骨髓或外周血分别进行流式细胞术检测及相关实验室检查。结果：MM患者骨髓浆细胞不仅数量明显增多，且形态明显异常，切片中浆细胞分布类型包括塞实型16例（45.71%），结节型14例（40.00%）和间质型5例（14.29%）。MM患者中出现血清LDH、β2-MG、Cr和BUN等检测指标升高的比例分别占80%、85.71%、62.86%和60%。MM患者浆细胞CD38、CD138均呈阳性表达，CD56、CD200、CD117和CD28阳性患者比例分别为65.71%、94.29%、60%和54.29%，CD20、CD81、CD33、CD27及CD13阳性患者比例分别为37.14%、42.86%、28.57%、57.14%和34.29%，而CD19及CD45阳性患者比例分别为22.86%和31.42%，且Igκ或Igλ链表达缺失呈单克隆增生。其中CD27和CD28的表达情况与MM患者预后密切相关，浆细胞CD27表达缺失及CD28阳性表达的患者5年总生存率较低（P < 0.05）。结论：MM患者骨髓中浆细胞免疫表型明显异常，其中CD27和CD28的表达与患者病情进展和临床预后具有显著相关性，因此免疫表型检测在MM患者临床诊断、治疗监测中具有重要意义。     

Expression of Adhesion Molecules on Myeloma Cells

We investigated the expression of adhesion molecules including LFA-1α (CD11a), Mac-1 (CD11b), LFA-1β (CD18), VLA-β₁, (CD29), H-CAM (CD44), VLA-4 (CD49d), VLA-5 (CD49e), ICAM-1 (CD54), N-CAM (CD56), LFA-3 (CD58), VNR-β (CD61), and LECAM-1 (CD62L) on fresh myeloma cells and human myeloma cell lines. By two-color flow cytometric analysis with anti-CD38 antibody, we demonstrated that myeloma cells were located in the strongly CD38-positive (CD38⁺⁺) fractions. Fresh myeloma cells were obtained from 28 patients with multiple myeloma (MM) and 3 patients with plasma cell leukemia (PCL). All myeloma cells expressed VLA-4 on their surface. Most of the myeloma cells also expressed VLA-5, ICAM-1, and LFA-3. H-CAM was strongly expressed in 3 cases of PCL and 2 cases of aggressive myeloma, and moderately expressed in other MMs. N-CAM was expressed in 68% of MMs, but none of the 3 PCLs. LFA-1 was expressed in two cases of aggressive myeloma, but not expressed in other non-aggressive myelomas. Most of the myeloma cells did not express Mac-1, VNR-β, or LECAM-1. These results suggest that VLA-4, VLA-5, ICAM-1, LFA-3, and H-CAM are involved in cellular interaction and migration in MM, and that the expression of N-CAM and LFA-1 varies with disease activity in MM.     

CD117 expression in glial tumors

Summary C-kit is a proto-oncogene involved in normal growth and development and neoplastic processes, and its product, CD117, is a highly specific immunohistochemical diagnostic marker for gastrointestinal stromal tumors (GISTs). Because GISTs that express immunohistochemically-detectable CD117 respond dramatically to treatment with tyrosine kinase inhibitors, identification of central nervous system tumors that express CD117 might open new therapeutic approaches for treatment of brain tumors. Specimens from 52 glial tumors of various histologic types and grades were assayed for CD117 immunoreactivity, and about 75% of the tumors were positive for CD117 expression; all except a few exhibited strong cytoplasmic and membranous staining. The proportion of high grade tumors of all tumor types with detectable CD117 immunoreactivity was statistically significantly greater than low grade tumors, and glioblastoma and anaplastic oligodendroglioma showed the highest staining grade. These findings support further investigation into the possibility that CD117 has an important role in growth of glial tumors and that patients with brain tumors expressing CD117 might benefit from treatment with receptor tyrosine kinase inhibitors.