DOG1、CD117和PDGFRA在胃肠道间质瘤中的表达及相关性

目的:探讨DOG1、CD117和血小板衍生生长因子受体α(PDGFRA)在胃肠道间质瘤(GISTs)诊断中的意义,并分析与其GISTs 临床病理因素和危险度的关系.方法:应用免疫组织化学Envision二步法检测63例GISTs及43例非GISTs间叶源性肿瘤患者中DOG1、CD117及PDGFRA的表达,并分析上述免...     

胃肠道间质瘤32例临床病理分析及免疫组化研究

目的：探讨胃肠道间质瘤的临床病理及免疫组化特点和诊断标准。方法：对32例胃肠道间质瘤进行常规病理检查及免疫组化染色。结果：胃肠道间质瘤由梭形细胞和上皮样细胞组成，大多数病例CD117和CD34标记阳性。结论：胃肠道间质瘤是胃肠道常见的非上皮性肿瘤，缺乏定向分化。CD117、CD34标记阳性对胃肠道间质瘤的诊断具有重要的价值。     

胃肠道间质瘤kit、人血小板衍生生长因子受体α基因突变分析与临床病理研究

胃肠道间质瘤(gastrointestinal stromal tumor,GIST)是由突变的kit[1]和人血小板衍生生长因子受体α( platelet derived growth factor receptor alpha,PDGFRA)[2]基因驱动的消化道最常见的间叶源性肿瘤.kit和PDGFRA突变的确定不仅可以评价原发疾病的预后[3],而且可以判断靶向治疗的获益情况[4].本研究对106例GIST标本行kit和PDGFRA基因突变检测,分析其与临床病理关系.     

Carney三联征临床病理分析1例

目的:探讨Carney三联征的临床病理特征、生物学行为及预后.方法:收集1例Carney三联征临床资料,光镜下观察其组织形态学特征并行免疫组织化学分析,对相关文献资料进行回顾分析与总结.结果:患者年轻女性,先后出现肺多发性软骨瘤及胃肠道间质瘤.镜下肺软骨瘤由境界清楚的软骨小叶构成,小叶间被纤维血管分隔;胃肠道间质瘤表现为胃黏膜下多发结节,镜下肿瘤细胞呈巢团状在肌壁间浸润性生长,瘤细胞呈上皮样,圆形或多角形,胞质丰富红染,显中度异型性,核分裂像易见;免疫组织化学染色肿瘤细胞CD34、CD117、Vimentin和PDGFRA阳性.结论:Carney三联征好发于年轻女性,包括肺多发性软骨瘤、胃肠道间质瘤和肾上腺外副神经节瘤,可同时出现,也可仅存在二联征.     

胃肠道间质瘤免疫组织化学特征

目的 研究胃肠道间质一些重要蛋白表达情况.方法 应用免疫组织化学方法对74例胃肠道间质瘤进行蛋白表达研究,进一步分析胃肠道质瘤免疫组化特征.结果 免疫组化评价中CD117在GISTs中阳性率为97.3％ (72/74),PDGFRA阳性率为55.4(41/74),DOG1阳性率为85.1％ (63/74),CD34阳性率为89.2％ (66/74),S100阳性率为12.2％(9/74),Desmin阳性率为5.4％ (4/74).结论 免疫组织化学染色是病理学诊断和鉴别诊断的重要手段,在疑难病例中CD117,PDGFRA,DOG1,和CD34等抗体联合应用是必要的.     

野生型胃肠道间质瘤的诊疗进展

胃肠道间质瘤(GIST)是最常见的消化道间叶组织来源肿瘤,约10%的患者不伴有KIT和PDGFRA基因突变,称为野生型GIST。根据发病机制,可分为琥珀酸脱氢酶(SDH)缺陷型、BRAF基因突变型和1型神经纤维瘤病(NF1)基因型等不同亚型,另有约半数患者的发病机制尚不明确。野生型GIST的临床特征、病理表现和疾病治疗均具有一定特殊性。本文就野生型GIST的分子基础、发病机制和临床诊疗进展作一综述。     

64排螺旋CT诊断胃肠道间质瘤的临床价值

目的探讨64排螺旋CT诊断胃肠道间质瘤的临床价值。方法对24例手术结果证实的胃肠道间质瘤患者的64排CT资料进行回顾性分析,并与临床病理表现对照。结果肿瘤起源于胃14例,空肠2例,回肠3例,结肠3例,腹腔网膜1例,肠系膜1例。黏膜下型3例,肌壁间型8例,浆膜下型14例。64排螺旋CT对于胃肠道间质瘤术前定性及定位准确率分别为91.6%（22/24）和95.8%（23/24）。结论 64排螺旋CT可以很好地显示胃肠道间质瘤的形态、部位、大小以及内部结构,能更准确地检出胃肠道间质瘤及初步定性。     

胃肠道间质瘤病理诊断新进展

胃肠道间质瘤(gastrointestinal stromal tumors,GIST)是一类胃肠道最常见的间叶源性肿瘤,由于特异的酪氨酸激酶受体c-kit或血小板转化生长因子(PDGFRA)突变而引起的.GIST病理诊断必须依据大体病理学、组织病理学、免疫组织化学检测结果以及基因检测结果综合判断,正确的术前病理诊断和危险度判定对患者进行个体化治疗有着非常重要的意义.本文系统阐述近年来关于GIST病理诊断的最新进展,以及国际国内对GIST危险度分级方案的最新共识.此外本文还总结了对GIST生物学行为评估有一定参考价值的分子生物学指标,供同道参考.     

胃肠道间质瘤97例临床分析

回顾性分析97例胃肠道间质瘤患者的临床资料。胃间质瘤占66.9％,4、肠间质瘤占32.1％。术前诊断率为68．8％。腹痛、腹部包块、便血、肠梗阻是本病最常见的临床症状。内镜、B超可作为首选检查,钡餐透视造影、数字减影血管造影（DSA）和CT检查能提高术前诊断率;术中快速病理检查可指导手术方案的选择。手术切除是胃肠道间质瘤的最佳治疗方法。     

胃肠道间质瘤

胃肠道间质瘤(GIST)是一种较少见的肿瘤，既往治疗主要以手术为主。随着病理研究的深入，发现大多数GIST存在c—kit前癌基因的变异，导致kit酪氨酸激酶持续活化，STI571是选择性酪氨酸激酶抑制剂，在胃肠道间质瘤靶向治疗方面起重要作用。对GIST的认识将对临床医师治疗本病有所帮助。现就GIST的流行病学、病理、临床表现、诊断及治疗进展等几方面进行综述。     

Platelet-derived growth factor receptor family mutations in gastrointestinal stromal tumours

OBJECTIVE: Activating mutations of either KIT or platelet-derived growth factor receptor alpha (PDGFRA) genes are present in the majority of gastrointestinal stromal tumours (GISTs). The type of gene mutation is associated with the aggressiveness of the disease, response to imatinib therapy, and the tumour site in the gastrointestinal tract. However, a subgroup of GISTs does not harbour these mutations. MATERIAL AND METHODS: Thirty-three GISTs were studied for mutations in exons encoding the juxtamembrane and the activation loop domains of KIT, PDGFRA, PDGFRB, CSF1R, and FLT3 genes using denaturing high-performance liquid chromatography and gene sequencing. RESULTS: Twenty-two (67%) GISTs had mutation in KIT and 3 (9%) in PDGFRA. The three PDGFRA mutations were all detected in exon 18 of the gene. Three of the 5 GISTs that had weak to moderate KIT expression had a PDGFRA mutation as compared to none of the 26 cases with strong KIT immunopositivity (p=0.022). No mutations were found in PDGFRB, CSF1R or FLT3 in the 8 cases that did not harbour KIT or PDGFRA mutations. CONCLUSIONS: KIT and PDGFRA are the most commonly mutated type III receptor tyrosine kinase genes in GIST. GISTs with PDGFRA mutations often have reduced expression of the KIT protein in immunohistochemistry, suggesting that immunohistochemistry may be potentially useful in identification of such GISTs.     

Intestinal neurofibromatosis is a subtype of familial GIST and results from a dominant activating mutation in PDGFRA

BACKGROUND & AIMS: Intestinal neurofibromatosis (Online Mendelian inheritance in Man database number 162220) is an alternate form of neurofibromatosis. Patients present with neurofibromas limited to the intestine in the absence of any other typical features of NF1 and NF2. At present, the molecular basis of intestinal neurofibromatosis remains elusive. The aim of the present study was to find the gene responsible for intestinal neurofibromatosis and to characterize functionally the mutation. METHODS: Three candidate genes (NF1, KIT, and PDGFRA) were screened for mutations in 3 sisters diagnosed with intestinal neurofibromatosis. Five tumors were available for pathologic examination. Activation (phosphorylation) of PDGFRalpha was subsequently tested by Western blot analysis on a transfected 293T and Ba/F3 cell line. RESULTS: We found an inherited mutation (Y555C) in the juxtamembrane domain of PDGFRA in the affected individuals. The Y555C mutation leads to autophosphorylation and thus activation of PDGFRalpha. These observations confirm that PDGFRalpha(Y555C) is an oncogenic kinase. The clinical phenotype in the reported family resembles the syndrome of familial gastrointestinal stromal tumors (familial GIST). Somatic activating mutations in KIT and PDGFRA are frequent in sporadic GISTs, and mutations in both genes have also been described in familial GISTs. The tumors in the reported family are morphologically identical to intestinal neurofibromas, but, immunohistochemically, they do not express S100 or any of the known GIST markers. CONCLUSIONS: The inherited PDGFRA mutation in the reported family shows that intestinal neurofibromatosis is allelic to familial GIST caused by PDGRA mutations. We therefore propose that these tumors be classified as familial KIT-negative gastrointestinal stromal tumors.     

Primary esophageal gastrointestinal stromal tumor with PDGFRA mutation

Gastrointestinal stromal tumors (GISTs) of the esophagus are a rare entity. Diagnosis of GIST is currently based on immunohistochemical staining of c-KIT or CD34. However, some tumors have clinicopathologic features of GIST but do not express c-KIT or CD34. A few GISTs contain mutations within a receptor tyrosine kinase protein, platelet-derived growth factor receptor alpha (PDGFRA). We herein report a case of esophageal GIST that was KIT negative and had a PDGFRA mutation. A 75-year-old male who had a giant submucosal tumor in the lower part of the thoracic esophagus underwent surgical resection. Immunohistochemical staining of the tumor revealed that it was uniformly negative for KIT, but partially positive for CD34, and negative for S-100 protein and smooth muscle actin (SMA), which led to the final diagnosis of GIST. PDGFRA genetic testing revealed a mutation in exon 12. The mitotic index was over 5/50 high-power fields, and necrotic changes were noted. Adjuvant chemotherapy using imatinib mesylate was administered. The patient has been disease free for 2 years. To the best of our knowledge, this is the only reported case of esophageal GIST that was KIT negative and had a PDGFRA mutation. In cases of digestive submucosal tumor that are difficult to diagnose because of c-KIT or CD34 negativity despite being suspicious for GIST, PDGFRA genetic testing may help for diagnosis of this minority type of GIST.     

Mutation assay of the novel gene <Emphasis Type="Italic">DOG1</Emphasis> in gastrointestinal stromal tumors (GISTs)

BACKGROUND: Recently, the novel gene DOG1 has been found to be overexpressed in most gastrointestinal stromal tumors (GISTs) specifically within the field of soft tissue tumors. DOG1 might play a role in development of GISTs and have potential as a diagnostic marker and therapeutic target, but the biological function and the overexpression mechanism have not yet been investigated. In this study we examined whether the DOG1 gene mutation occurs as with the KIT gene and PDGFRA gene. METHODS: We investigated ten resected primary GIST tissues. All cases were examined for immunoreactivity for KIT and DOG1 and screened for mutation in the KIT gene (exons 9, 11, 13, and 17) and the PDGFRA gene (exons 12, 14, and 18) by direct DNA sequencing. Four cases with relatively good quality DNA were analyzed for the DOG1 gene (exons 1-26) mutation. RESULTS: All ten GISTs showed immunoreactivity for KIT. Although all cases expressed DOG1 in immunohistochemistry, we could not find any mutations within all 26 exons (a total of 104 exons) of the DOG1 gene in the four analyzed cases. CONCLUSIONS: Based on four cases, the DOG1 gene was found not to be mutated in GISTs.     

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.     

Treatment of patients with advanced gastrointestinal stromal tumor of small bowel： Implications of imatinib mesylate

AIM: To examine the impact of imatinib mesylate (Glivec) on patient survival and response and its safety,and the correlation of the response rate with the kit gene mutation status. METHODS: Thirty-three of 74 (44.6%) small bowel gastrointestinal stromal tumor (GIST) patients who developed recurrence after curative resection and not treated with Glivec were classified as group A patients. Twenty-two advanced small bowel GIST patients treated with Glivec were classified as group B patients. Clinicopathological features, post-recurrence and overall survival rates were compared. Each tumor in group B patients was investigated for mutations of kit or plateletderived growth factor alpha (PDGFRA). The mutation type was correlated with clinical outcomes. The antitumor effect and safety of Glivec in group B patients were also assessed. RESULTS: Advanced small bowel GIST patients treated with Glivec had substantially longer post-recurrence survival and higher overall survival rates than those not treated with Glivec. A total of 15 patients had a partial response (PR) (67.8%). Activated mutations of c-kit were found in 16 of 19 tested patients and no PDGFRA mutant was identified. In 13 patients with GISTs harboring exon 11 kit mutations, the partial response rate (PR) was 69.3%, whereas two of three patients with tumors containing an exon 9 kit mutation had an overall response rate (ORR) of 66.7% (not significant). CONCLUSION: Glivec significantly prolongs the post-recurrence and overall survival of Asian patients with advanced GISTs. Glivec induces a sustained objective response in more than half of Asian patients with advanced small bowel GISTs. Activated mutations of kit exon 11 are detectable in the vast majority of GISTs. There is no difference in the PR rate for patients whose GISTs have kit exon 9 and exon 11 mutations.     

Mechanisms of resistance to imatinib mesylate in gastrointestinal stromal tumors and activity of the PKC412 inhibitor against imatinib-resistant mutants

BACKGROUND AND AIMS: Resistance is a major challenge in the treatment of patients with gastrointestinal stromal tumors (GISTs). We investigated the mechanisms of resistance in patients with progressive GISTs with primary KIT mutations and the efficacy of the kinase inhibitor PKC412 for the inhibition of imatinib-resistant mutants. METHODS: We performed a cytogenetic analysis and screened for mutations of the KIT and PDGFRA kinase domains in 26 resistant GISTs. KIT autophosphorylation status was assessed by Western immunoblotting. Imatinib-resistant GIST cells and Ba/F3 cells expressing these mutant proteins were tested for sensitivity to imatinib and PKC412. RESULTS: Six distinct secondary mutations in KIT were detected in 12 progressive tumors, with V654A and T670I found to be recurrent. One progressive tumor showed acquired PDGFRA -D842V mutation. Amplification of KIT or KIT / PDGFRA was found in 2 patients. Eight of 10 progressive tumors available for analysis showed phosphorylated KIT. Two remaining progressive tumors lost KIT protein expression. GIST cells carrying KIT -del557-558/T670I or KIT -InsAY502-503/V654A mutations were resistant to imatinib, while PKC412 significantly inhibited autophosporylation of these mutants. Resistance to imatinib and sensitivity to PKC412 of KIT -T670I and PDGFRA -D842V mutants was confirmed using Ba/F3 cells. CONCLUSIONS: This study shows the high frequency of KIT/PDGFRA kinase domain mutations in patients with secondary resistance and defines genomic amplification of KIT / PDGFRA as an alternative cause of resistance to the drug. In a subset of patients, cancer cells lost their dependence on the targeted tyrosine kinase. Our findings show the sensitivity of the imatinib-resistant KIT -T670I and KIT -V654A and of PDGFRA -D842V mutants to PKC412.     

KIT exon 11 codon 557/558 deletion/insertion mutations define a subset of gastrointestinal stromal tumors with malignant potential

AIM： To study the association of the frequency and pattern of KIT and PDGFRA mutations and clinicopathological factors in a group of patients with gastrointestinal stromal tumors （GIST）. METHODS： Thirty patients with GIST were examined. Exons 9, 11, 13, and 17 of the KIT and exons 12 and 18 of the PDGFRA gene were analyzed for the presence of mutations by PCR amplification and direct sequencing. RESULTS： KIT or PDGFRA mutations were detected in 21 of the 30 patients （70%）. Sixteen patients had mutations within KIT exon 11, three within KIT exon 9, and two within PDGFRA exon 18. GISTs with KIT exon 9 mutations were predominantly located in the small intestine, showed a spindle cell phenotype, and were assessed as potentially malignant. GISTs with KIT exon 11 mutations were located in the stomach and intestine, showed mainly a spindle cell phenotype, and were scored as potentially malignant （P 〈 0.05）. Tumors with KIT exon 11 codon 557/558 deletion/insertion mutations were found to be associated with a potentially malignant clinical behaviour （P 〈 0.003）. GISTs with PDGFRA mutations located in stomach showed a mixed cell phenotype and were classified as of very low or low moderate malignant potential. CONCLUSION： Determination of KIT and PDGFRA mutations should be additional parameters for the better prediction of GISTs clinical behaviour. Tumors with deletion/insertion mutations affecting codons 557/558 of the KIT gene seem to represent a distinct subset of malignant GISTs.