Expression of DOG1, PDGFRA, and p16 in Gastrointestinal Stromal Tumors

Background/Aims

The diagnosis of gastrointestinal stromal tumors (GIST) relies on the demonstration of KIT expression, but KIT expression is absent or reduced in approximately 15% of GIST.

Methods

Eighty-one GISTs were diagnosed between January 1998 and December 2007 at the Department of Pathology at both Chungnam National University Hospital and Eulji University Hospital, Daejeon. Medical history, patient follow-up, and radiographic data were collected if available in the medical records. To determine diagnostic and prognostic markers for GISTs focused on PDGFRA mutation and clinicopathologic features, we analyzed 81 GIST cases for KIT, PDGFRA, DOG1, and p16 expression and for mutation of PDGFRA genes.

Results

Among 81 GIST cases, 20 high risk cases (24.7%) were recurred or metastasized. Immunohistochemically, KIT was positive in 76 (93.8%), PDGFRA in 75 (92.7%), and DOG1 in 77 (95.1%). With a cutoff value of 50%, p16 expression was positive in 26 cases were positive (32.1%). A correlation between p16 expression or negative DOG1 expression and recurrence or metastasis was demonstrated (p<0.05). Four cases showed a missense mutation in exon 12 of PDGFRA gene, three of these were of epithelioid GISTs. Two cases showed a silent mutation in exon 18 of PDGFRA.

Conclusions

These results indicate that the expression of DOG1 and PDGFRA is observed in a majority of GIST cases. Expression of p16 and negative DOG1 expression is predictive for development of recurrence and/or metastasis. Even though mutation of the PDGFRA gene is frequently seen in epithelioid GISTs, a clinicopathologic correlation was not demonstrated.     

Novel protein kinase C, nPKC, inhibition of murine bumetanide-sensitive Na+,K+,2Cl- cotransporter BSC1 in Xenopus oocyte

 In vitro transcribed RNAs obtained for the absorptive type of Na,K,2Cl cotransporter BSC1, isoform F, and either of three deletion mutants were injected into oocytes, while oocytes injected with water served as controls. Wild-type cRNA induced a bumetanide-sensitive Rb flux after 18 h which rose to a maximum of about 600 pmol · (h·oocyte)^–1 during the next 24 h. This level of flux lasted for at least 31/2 days. All deletion mutants were either not expressed and/or were non-functional. The protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) eliminated the induced flux, with an apparent dissociation constant (aK _i) of 6 nM. A 15 nM PMA-elicited inhibition of Rb flux was blocked by the PKC inhibitor calphostin C (200 nM) to ≈80%, while PKC inhibitors staurosporine (40 nM) and G?6976 (50 nM) were ineffective. The phosphatase inhibitor okadaic acid (4.6 nM) did not influence PMA-induced flux inhibition. The PKC activator sn-1,2-dioctanoyl glycerol (DOG), even at 2 μM, did not inhibit bumetanide-sensitive Rb influx. The induced Rb fluxes were not affected by PKA or PKG, as stimulation by either 0.5 mM dibutyryl-cAMP, 0.5 mM dibutyryl-cGMP, 10 μM forskolin, and/or 0.5 mM theophylline had no effect on bumetanide-sensitive Rb fluxes. Activating endogenous muscarinic receptors with 20 μM acetylcholine had no effect on expressed BSC1 fluxes. The sensitivity to bumetanide of induced Rb flux had an aK _i of around 70 nM. Attempts to follow the expression of BSC1 in plasma membranes with either immunoblotting or radio-methionine pulse-chase were unsuccessful. We conclude that a PKC, likely of the novel type, nPKC, seems to be involved in PMA-induced reduction of expressed BSC1 and/or its ion transport function. Received: 5 December 1997 / Received after revision: 9 February 1998 / Accepted: 10 February 1998     

DOG1 and CD117 are the antibodies of choice in the diagnosis of gastrointestinal stromal tumours

Novelli M, Rossi S, Rodriguez‐Justo M, Taniere P, Seddon B, Toffolatti L, Sartor C, Hogendoorn P C W, Sciot R, Van Glabbeke M, Verweij J, Blay J Y, Hohenberger P, Flanagan A & Dei Tos A P
(2010) Histopathology 57 , 259–270
DOG1 and CD117 are the antibodies of choice in the diagnosis of gastrointestinal stromal tumours Aims: The histopathological diagnosis of gastrointestinal stromal tumours (GIST) is typically made based on a combination of clinical and morphological features supported by immunohistochemistry studies. The aim of this study was to examine the staining quality, sensitivity, specificity and utility of antibodies used commonly in GIST diagnosis. Methods and results: Immunohistochemistry with a panel of antibodies [CD117, DOG1, protein kinase C (PKC)‐theta, nestin, CD34, smooth muscle actin (SMA), desmin, S100 and CD171] was performed on whole sections from 187 GIST and 29 gastrointestinal mesenchymal tumours, and on several microarrays including 355 GISTs and 120 soft tissue sarcomas. Results showed that DOG1 and CD117 were the most sensitive and specific antibodies used in GIST diagnosis. PKC‐theta and nestin were sensitive, but less specific, also staining other spindle cell tumours commonly considered in the differential diagnosis of GIST. CD34 staining was less sensitive than many of the other antibodies and of limited aid in diagnosis. The smooth muscle markers SMA and desmin, together with the neural marker S100, were unhelpful in confirming a diagnosis of GIST, but were particularly useful in the exclusion/diagnosis of other gastrointestinal mesenchymal tumour types. Conclusions: In the majority of histologically suspected GISTs a combination of CD117 and DOG1 immunostaining is sufficient to confirm the histological diagnosis.     

Diagnostic role of DOG1 and p63 immunohistochemistry in salivary gland carcinomas

Background: The differential diagnosis of salivary carcinomas is always difficult and challenging. Salivary neoplasms often shows more than one growth pattern and significant morphologic variability may exist within a single tumor and between different tumors. The aim of this study was to examine the role of DOG1 (discovered on gastrointestinal tumor-1) and p63 immunohistochemistry in the diagnosis and differential diagnosis of salivary carcinomas. Methods: we examined the expression of DOG1 and p63 immunohistochemistry in 33 mucoepidermoid carcinomas (MEC), 9 acinic cell carcinomas (ACC), 10 adenoid cystic carcinomas (AdCC) and 4 myoepithelial carcinomas. Results: All ACC showed strong to moderate positivity for DOG1 (P=0.001) and all were totally negative for p63. All MEC expressed strong to moderate positivity for p63 (P=0.001) while only (9.1%) were weak to moderately positive for DOG1. (80%) AdCC were moderately positive for DOG1 in ductal and myoepithelial components and (100%) showed moderate positivity for p63 in myoepithelial cells only (P=0.001). All myoepithelial carcinomas were DOG1 negative, 2 (50%) were weakly positive for p63 while the other 2 were moderately positive (P=0.5). Conclusion: DOG1 is a sensitive marker in the diagnosis of acinic cell carcinoma, p63 is sensitive in the diagnosis of mucoepidermoid carcinoma, the combined use of both markers is helpful and statistically significant in the differential diagnosis of acinic cell carcinoma versus mucoepidermoid carcinoma, both markers can help in the diagnosis of adenoid cystic carcinoma but they have no role in the diagnosis of myoepithelial carcinoma.     

CD117、PDGFRA蛋白单独及联合DOG1检测在胃肠道间质瘤中的诊断价值

目的:探讨组织中CD117、PDGFRA两种蛋白表达在胃肠道间质瘤(gastrointestinal stromal tumors,GIST)中的诊断价值及联合DOG1蛋白检测的意义。方法:回顾性对99例GIST和25例非GIST肿瘤标本进行CD117、PDGFRA和DOG1蛋白表达进行检测并进行相关性分析。结果:GIST组CD117、PDGFRA和DOG1蛋白表达率分别为93.94%(93/99)、53.54%(53/99)和90.91%(90/99),非GIST组分别为4.00%(1/25)、4.00%(1/25)和12.00%(3/25),组间比较均有统计学意义(P<0.05);GIST组性别、年龄、肿瘤直径、肿瘤部位、组织学类型和危险度分级等临床病理参数与CD117、PDGFRA和DOG1蛋白表达无统计学意义(P>0.05);CD117、PDGFRA、DOG1、CD117和DOG1联合、PDGFRA和DOG1联合及三者联合判断GIST的敏感性分别为0.989、0.981、0.968、0.960、0.933和0.961,特异性分别为0.800、0.343、0.710、0.840、0.947和0.955,ROC曲线下面积(AUC)分别为0.945、0.748、0.895、0.895、0.840和0.975。结论:GIST中CD117、PDGFRA及DOG1蛋白表达在胃肠道间质瘤中的优势人群有待进一步研究;CD117、PDGFRA蛋白单独及联合DOG1检测可提高对GIST诊断的准确度。     

Presence of PDGFRA and DOG1 mutations in gastrointestinal stromal tumors among Chinese population

Approximately 15% of gastrointestinal stromal tumors (GIST) do not express KIT mutations and of these about 5 to 7% harbor mutations in PDGFRA. DOG1 was specifically expressed in GISTs. These cases require special attention for PDGFRA and DOG1 mutational status. Hundred cases of GIST were diagnosed between August 2007 and October 2012 at the First Affiliated Hospital of Guangxi Medical University. DNA from tumor tissues and normal adjacent tissues was isolated and amplified for the 22 exons of PDGFRA and 26 exons of DOG1. Each PCR product was sequenced. Amino acid sequences were inferred from DNA and aligned to GenBank reference sequences to determine the position and type of mutations. Overall, 16.0% of the samples had a mutation in PDGFRA, and GISTs with mutations in the DOG1 gene were not found. Of the mutations detected, they were in PDGFRA exon 18 (8 cases, 8%), PDGFRA exon 12 (5 cases, 5%), PDGFRA exon 14 (1 cases, 1.0%), PDGFRA exon 11 (1 cases, 1.0%), and PDGFRA exon 8 (1 cases, 1.0%). Of these, Y392S, L521P and T632K mutant occurred in PDGFRA exon 8, exon 11 and exon 14, respectively. The mutation of PDGFRA has been considered as another causative genetic event as PDGFRA mutations were found in most GISTs lacking a KIT mutation. PDGFRA mutations occurred preferentially in exon 18 and exon 12. Mutations occurring in PDGFRA exon 8 (Y392S), exon 11 (L521P) and exon 14 (T632K) also were first identified. The over-expression of DOG1 was not related to DOG1 gene mutation.     

胃肠道间质瘤临床病理及免疫组化表达的分析

目的探讨胃肠道间质瘤(GIST)的临床病理和免疫组织化学特征。方法回顾性分析181例经手术治疗的GIST患者临床病理资料,并检测CD117、DOG1、CD34、SMA、Desmin、S100的表达。结果 GIST形态学表现以梭形细胞型为主。CD117、DOG1、CD34、SMA、Desmin、S100阳性表达率分别为:91.2%、89.5%、77.9%、35.6%、6.1%、11.0%。CD117与DOG1阳性表达一致率为83.4%(151/181),DOG1在68.8%(11/16)的CD117阴性GIST中阳性表达。GIST组织中仅DOG1的阳性表达与患者年龄、肿瘤大小、危险度分级有关(P<0.05),其他标记物与GIST临床病理因素均无关。结论 CD117和DOG1是诊断GIST敏感而有效的指标,联合检测CD117、CD34和DOG1可提高GIST诊断的准确率;SMA、Desmin、S100是重要的鉴别诊断指标;DOG1阴性表达可能提示GIST预后不良。     

新型胃肠道间质瘤标记物DOG1的应用与探讨

目的 探讨新型胃肠道间质瘤（GIST）标记物DOG1的敏感性和特异性。方法 收集50例胃肠道间质瘤的完整临床资料及病理资料。复读切片,行免疫组化CD117、PDGFRA、DOG1标记,进行比较。另收集20例非GIST而CD117阳性的病例行DOG1标记。结果 在不同危险程度分级,CD117、PDGFRA阴性、弱阳性、阳性的病例,DOG1均呈较强的阳性表达。另20例非GIST而CD117阳性病例,DOG1则多为阴性或弱阳性。结论 DOG1是敏感、特异的胃肠道间质瘤标记物。DOG1与CD117、PDGFRA的联合使用进一步完善了诊断依据,不论对明确诊断或术后个性化靶向治疗,都有着非常重要的意义。     

胃肠间质瘤相关基因表达及突变的研究

目的 分析胃肠间质瘤（GISTs）中DOG1、CD117与类胰岛素生长因子1受体（IGF1R）的表达以及c-KIT和PDGFRA基因突变情况,并探讨它们与GISTs临床病理特征的关系及意义。方法 免疫组化检测98例GISTs中DOG1、CD117和IGF1R的表达情况及40例非GISTs间叶源性肿瘤中DOG1和CD117的表达情况。基质辅助激光解析电离飞行时间质谱法检测77例GISTs中c-KIT和PDGFRA基因突变情况。结果 GISTs中DOG1、CD117及IGF1R的阳性表达率分别为92.9％、95.9％和6.1％,非GISTs间叶源性肿瘤中DOG1和CD117阳性表达率分别为10.0％和17.5％,两者中DOG1和CD117阳性表达率的差异有统计学意义（P＜0.001）。GISTs中DOG1的表达与肿瘤大小及危险度有关,CD117表达与肿瘤部位及组织学类型有关,IGF1R表达与临床病理特征无关。77例GISTs中c-KIT、PDGFRA基因的突变率分别为64.9％和22.1％,两个基因分别以外显子11（54.0％）和外显子12（16.9％）突变最多见。c-KIT、PDGFRA基因突变仅与肿瘤部位有关（P=0.001,P=0.002）。CD117、DOG1的表达与c-KIT和PDGFRA基因是否突变无关,而野生型及突变型（存在c-KIT或PDGFRA基因突变）GISTs中IGF1R表达差异有统计学意义。结论 联合检测DOG1、CD117可以提高诊断GISTs的准确性,尤其是CD117表达,两者均与临床病理特征有关。IGF1R可能是野生型GISTs特异性的免疫组化指标和潜在治疗靶点。将肿瘤原发部位与基因突变检测结果相结合,对预测GISTs患者应用酪氨酸激酶抑制剂的疗效以及预后更具指导价值。