摘要目的:探讨骨巨细胞瘤（giant cell tumor of bone，GCTB）H3.3免疫组织化学阴性病例存在的H3F3A 基因突变类型。方法:收集2017年1月至2019年1月就诊于北京积水潭医院的181例GCTB，行光镜观察并结合临床影像学明确诊断。EnVision二步法免疫组织化学H3.3染色检测H3F3A G34W突变蛋白的表达，对免疫组织化学结果阴性的病例采用Sanger测序法检测H3F3A基因的突变类型。结果:免疫组织化学H3.3以细胞核阳性反应为阳性标准，181例GCTB：阳性164例，阴性17例，阳性率90.61%。对免疫组织化学结果阴性的17例采用DNA Sanger测序法检测H3F3A基因突变情况。测序结果显示8例存在突变，分别为：3例G34L（glycine 34 to leucine，3/181，1.66%），3例G34V（glycine 34 to valine，3/181，1.66%），2例G34R（glycine 34 to arginine，2/181，1.10%），其余9例均为野生型（glycine 34，9/181，4.97%）。经测序分析证实免疫组织化学H3.3阴性的病例中并无G34W突变。H3.3免疫组织化学结合测序分析，诊断GCTB总体阳性率可达95.03%。结论:H3.3免疫组织化学可检测存在H3F3A G34W突变的GCTB，对其他罕见突变类型及野生型不具诊断价值。

abstractsObjective:To investigate the subtypes of H3F3A DNA mutation in H3.3 immunohistochemistry (IHC) negative giant cell tumors of bone (GCTB).Methods:IHC expression of G34W mutated protein was evaluated in 181 cases GCTB. In H3.3 IHC negative cases, Sanger DNA sequencing analysis was used to detect the subtypes H3F3A mutations.Results:Overall, 164 (90.61%) cases of GCTB showed nuclear expression of H3.3, and 17 cases were negative. These 17 H3.3 negative cases were subjected to Sanger DNA sequencing analysis; results showed that eight presented rare mutation subtypes occurring at glycine 34 to leucine (G34L, 3/181, 1.66%), glycine 34 to valine (G34V, 3/181, 1.66%) and glycine 34 to arginine (G34R, 2/181, 1.10%), and the other nine cases were wild type (glycine 34, 9/181, 4.97%). Sanger DNA sequencing analysis confirmed the absence of G34W mutation in the H3.3 negative cases. Combining IHC and DNA sequencing analysis increased the detection rate of H3F3A mutation in the GCTB to 95.03%.Conclusions:H3.3 IHC could detect H3F3A G34W mutation in GCTB, but not for other rare mutation and wild types loci.