BRA FV600E突变特异性抗体在胃肠道间质瘤中的应用

Application of BRAF V600E mutation-specific immunohistochemistry in diagnosis of gastrointestinal stromal tumors

目的探讨BRAF V600E特异性抗体在胃肠道间质瘤（GIST）中的敏感性及特异性。方法使用BRAF V600E突变特异性抗体（VE1）检测14例KIT或血小板衍生生长因子受体A（PDGFRA）突变及10例KIT/PDGFRA野生的GIST病例，并与Sanger测序结果进行验证。结果24例GIST患者中11例男性，13例女性，中位年龄54岁（29～75岁）；发生于胃16例、小肠7例、腹腔1例。BRAF V600E胞质弥漫强阳性表达4例（16.7%，4/24），弱阳性1例（4.2%，1/24），阴性19例（79.2%，19/24）。其中强阳性病例经测序验证为BRAF基因V600E突变，其发病部位3例位于胃，1例位于小肠，组织学形态均为梭形细胞型。除1例小肠的病例危险度分级为高危险度外，其余病例均为极低或低危险度。测序检测BRAF V600E弱阳性或阴性表达的病例没有发现BRAF V600E突变。结论BRAF V600E特异性抗体（VE1）是GIST中检测BRAF突变一种高敏感性及特异性的方法，可以大范围应用于临床检测。

Objective To evaluate the utility of BRAF V6OOE allele-specific antibody in the diagnosis of gastrointestinal stromal tumors （GISTs）. Methods BRAF V6OOE mutation-specific immunohistochemistry and BRAF sequencing were performed in 24 consecutive GISTs, including 14 cases of KIT or PDGFRA mutations and l0 cases of KIT/PDGFRA wild GISTs. Results GISTs of 11 men and 13 women with a mean age 54 years（ range 29 -75 years） were included with tumors arising from stomach （16 cases）, small bowel （7 cases）, and peritoneal cavity （1 case）. Strong and diffuse cytoplasmic BRAF staining was noted in 4 of 24 cases （ 17% ） , while 1 of 24 cases （4%） showed weak staining, and 19 of 24 cases （79%） had no staining. The four cases with strong BRAF immunostain were confirmed to have BRAF mutations, including 3 cases in the stomach and 1 case in the small intestine. All tumors showed spindle cell morphology. Only one case had progressive disease. No BRAF mutations were detected in cases with weak or negative BRAF immunostain. Conclusion BRAF V600E mutation-specific immunohistochemistry is a highly sensitive and specific marker for detecting BRAF-mutated GISTs.