Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
Dermatologic Diagnostic Centre, Unit of Dermatology, Department of Medicine, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
JAMA Dermatol. 2015 Apr;151(4):410-6. doi: 10.1001/jamadermatol.2014.3689.
BRAFV600E mutations are present in approximately 50% of cutaneous malignant melanomas (CMMs). The use of BRAFV600E mutation-specific monoclonal antibody VE1 immunohistochemical analysis may facilitate rapid detection of BRAFV600E mutations in CMMs and demonstrate heterogeneity among tumors.
To characterize the pattern of BRAFV600E protein expression in primary CMMs with matched metastases and to analyze the use of VE1 immunohistochemical analysis in clinical practice using formalin-fixed, paraffin-embedded tumor tissue.
DESIGN, SETTING, AND PARTICIPANTS: In this retrospective cohort study performed at Karolinska University Hospital from September 2012 to September 2013, we examined CMMs (124 primary tumors and 76 metastases) with VE1 immunohistochemical analysis, and results were compared with DNA mutation analyses.
Determination of intratumoral and intertumoral heterogeneity as well as the sensitivity and specificity of VE1 immunohistochemical analysis.
Positive staining results with the VE1 antibody were detected in 94 of 200 tumors (47.0%). In general, VE1 staining was homogeneous. However, VE1 staining intensity varied among the primary tumors and corresponding metastases in 63 of 135 tumors (46.7%), but a change of mutational status based on DNA analysis was found in only 4 matched tumors (3.0%). Discordant findings between DNA mutation analysis and immunohistochemical analysis were observed in 12 tumors. The overall sensitivity and specificity of VE1 immunohistochemical analysis were 96.7% and 94.5%, respectively. A comparable sensitivity was obtained for primary and metastatic CMMs. The specificity was lower among primary CMMs (92.4%) compared with metastases (98.0%).
We found VE1 immunohistochemical analysis to be a useful and rapid assay for BRAFV600E mutations that may contribute to the detection of intratumoral and intertumoral heterogenetic subclones. Tumors with positive results, including strong staining, should be expedited for confirmatory BRAF mutation testing. If this test result is negative, a false-negative result of the mutation analysis should be considered. Validation of VE1 immunohistochemical analysis in clinical practice is needed.
BRAFV600E 突变存在于约 50%的皮肤恶性黑色素瘤（CMM）中。BRAFV600E 突变特异性单克隆抗体 VE1 的免疫组织化学分析的使用可以促进 CMM 中 BRAFV600E 突变的快速检测，并显示肿瘤之间的异质性。
描述原发性 CMM 中 BRAFV600E 蛋白表达的模式，并用福尔马林固定、石蜡包埋的肿瘤组织分析 VE1 免疫组织化学分析在临床实践中的应用。
设计、地点和参与者：这项回顾性队列研究于 2012 年 9 月至 2013 年 9 月在卡罗林斯卡大学医院进行，我们用 VE1 免疫组织化学分析检查了 CMM（124 个原发性肿瘤和 76 个转移瘤），并将结果与 DNA 突变分析进行了比较。
确定肿瘤内和肿瘤间的异质性以及 VE1 免疫组织化学分析的敏感性和特异性。
用 VE1 抗体检测到 200 个肿瘤中的 94 个（47.0%）呈阳性染色结果。通常，VE1 染色是均匀的。然而，在 135 个肿瘤中有 63 个（46.7%），原发性肿瘤和相应的转移瘤之间的 VE1 染色强度不同，但只有 4 个匹配的肿瘤（3.0%）基于 DNA 分析发现了突变状态的变化。在 12 个肿瘤中观察到 DNA 突变分析和免疫组织化学分析之间的不一致发现。VE1 免疫组织化学分析的总敏感性和特异性分别为 96.7%和 94.5%。原发性和转移性 CMM 的敏感性相当。与转移瘤（98.0%）相比，原发性 CMM 的特异性较低（92.4%）。
我们发现 VE1 免疫组织化学分析是一种有用的快速 BRAFV600E 突变检测方法，可能有助于检测肿瘤内和肿瘤间的异质性亚克隆。包括强染色在内的阳性结果的肿瘤应加快进行 BRAF 突变确认检测。如果该检测结果为阴性，则应考虑突变分析的假阴性结果。需要在临床实践中验证 VE1 免疫组织化学分析。
