中国人群朗格汉斯组织细胞增生症患者BRAF V600E突变及临床意义

BRAF V600E Mutation in Chinese Patients with Langerhans Cell Histiocytosis and Its Clinical Significance

目的:探讨中国人群朗格汉斯组织细胞增生症(Langerhans cell histiocytosis,LCH)的BRAF V600E突变情况及其临床意义。方法:回顾性分析50例经病理诊断的LCH患者临床资料并对石蜡包埋的活检组织进行BRAF V600E的检测。全部病例采用免疫组化法检测BRAF V600E突变蛋白的表达,部分病例同时采用HRM-Sanger测序法进行基因检测(31例)。结果:本研究组中LCH患者BRAF V600E总体突变率为58%(29/50),免疫组化法测定阳性率为56%(28/50);而HRM-Sanger测序法阳性率为54.8%(17/31)。在14例基因检测阴性患者中2例突变蛋白检测阳性(2/14,14.3%);17例患者基因检测阳性中有1例患者突变蛋白检测呈阴性(1/17,5.9%);BRAF V600E突变与年龄、性别、临床分级及治疗反应均无显著相关性,突变患者与野生型患者的3年总体存活和无病存活时间也无统计学差别。结论:免疫组织化学法检测石蜡包埋组织中BRAF V600E突变具有较高的敏感性。58%的中国人群LCH患者存在BRAF V600E突变,提示该病是一种克隆性疾病,但是其临床意义有待进一步研究。

Objective： To investigate the BRAF V600E mutation in Chinese patients with langerhans cell histiocytosis （LCH） and its clinical significance. Methods： The clinical records of 50 pathology-diagnosed LCH cases were analyzed retrospectively and the Paraffin-embedded tissue blocks were retrieved to test the BRAF V600E mutation by immunohistochemical method with a specific BRAF V600E protein antibody. BRAF V600E mutation was also tested by High-resolution Melting Analysis （HRM） followed by Sanger sequence in 31 cases. Results; BRAF V600E mutation was found in 58% （29/50） LCH cases by gene test or protein test. BRAF V600E expression was identified in 56% （28/ 50） LCH cases by immunohistochemical analysis alone while 54.8% （17/31）by HRM-Sanger alone. Two out of 14 cases, who were negative for BRAF V600E by HRM-Sanger analysis, were positive by immunohistochemical tests （14. 3% ）. Otherwhile, only 1 out of 17 LCH cases with a positive BRAF V600E mutation by gene test were negative by immunohistochemical analysis. The status of BRAF V600E did not show significant relevance with age, sex, clinical stage or response. Also, BRAF V600E had no effect on the 3-year survival or event-free survival in this group. Conclusion： Immunohistochemical tests for BRAF V600E in Paraffin-embedded tissue is of ideal sensitivity, 58% Chinese LCH patients have BRAF V600E positive and so LCH is a clonal disease but the exact role of BRAF V600E in LCH needs further research.