摘要目的 探讨腹腔内胃肠道外间质瘤(EGIST)中c-kit和血小板衍生生长因子受体α(PDGFR-α)基因突变、临床病理特征和预后的影响因素.方法 应用免疫组织化学方法检测23例EGIST中CD117、CD34和Ki-67蛋白的表达,应用PCR扩增和基因测序的方法检测c-kit和PDGFR-α基因突变,结合临床病理特征分析影响EGIST患者预后的相关因素.采用Kaplan-Meier法和COX比例风险模型比较不同因素对生存的影响.结果 本组c-kit基因的突变率为44%,均为第11号外显子突变;PDGFR-α基因的突变率是13%,均为第18号外显子的突变(D842V点突变).CD117表达阳性率是100%,CD34表达阳性率为74%.Ki-67指数:＜1%者占30%,1%～5%者占44%,＞5%者占26%.生存分析显示,核分裂象数目(P=0.025)和Ki-67指数(P=0.032)与疾病相关生存时间相关.结论 EGIST有着与GIST相似的c-kit和PDGFR-α基因突变位点,并且c-kit基因突变频率也相近,但是PDGFR-α基因突变频率较GIST稍高.可以将EGIST作为GIST的一个特殊亚型.结合核分裂象和Ki-67指数对EGIST进行分级是判断预后的一个较好的标准.

abstractsObjective To evaluate prognostic significance of c-kit and PDGFR-α gene mutation in extragastrointestinal stromal tumors(EGIST). Methods Paraffin embedded tissue specimens from 23 EGISTs were tested for CD117,CD34 and Ki-67 expression by immunohistochemical method.EGIST cases were also tested for the presence of c-kit exons 9,11,13,17 mutations and PDGFR-α exons 12,18 mutations.Kaplan-meier survival rate was used to evaluate the prognostic factors. Results Of 23 cases of EGIST,23(100%)were positive for CD117,17(74%)were positive for CD34.For Ki-67 labeling index(Ki-67 LI):30%were＜1%,44%were between 1%-5%,26%were＞5%.C-kit mutations were detected in 44% of EGIST patients and all were of exon 11 mutations.PDGFR-α mutations were found in 13%of all the 23 cases and all were of exon 18 mutations(The commonest type of mutation D842V).Survival analysis indicated that mitotic count and Ki-67 index were significant predictors for survival.Conclusion The pattern of c-kit and PDGFR-α mutation in EGIST was essentially similar to that in GIST.But the mutation frequency of PDGFR-α was slightly higher in EGIST than in GIST.EGIST could be a special subtype of GIST.The results of this study also show combination of mitotic counts and Ki-67 labeling index may be useful for predicting the prognosis of EGIST.