Patients with NTRK-rearranged tumors can be now treated using anti-TRK–targeted therapies making NTRK testing important for treatment choices in patients with advanced cancers. Pan-TRK immunohistochemistry (IHC) could be a valuable premolecular screening strategy in this field. The choice of 1 IHC method or another requires to investigate for intermethod comparison. A high frequency of pan-TRK positive tumors among salivary gland tumors makes these tumors particularly appropriate for such a technical study. In this work, we studied the intermethod agreement for 2 pan-TRK IHC methods (using A7H6R and EPR17341 clones) in a file of salivary gland tumors of different subtypes. Among 71 tumors, pan-TRK IHC was diagnosed as positive (ie, H score ≥5) in 23 and 18 cases using EPR17341 and A7H6R clones, respectively, with a good intermethod agreement in terms of positive/negative result (κ, 0.70) but only a moderate agreement considering the H score values themselves (intraclass correlation coefficient of 0.5399). Beyond the intensity of staining and the percentages of stained cells, major differences were also observed between the location and type of cells stained in positive cases between the 2 clones. The single NTRK-rearranged case in our series (ie, a NTRK3-rearranged salivary secretory carcinoma) was positive with the 2 pan-TRK antibodies. Future studies including molecularly proven NTRK-rearranged tumors remain required to further study and compare the performances of different pan-TRK clones in the screening of NTRK-rearranged cancers but it is now obvious that the staining patterns of A7H6R and EPR17341 clones are not strictly identical.

中文翻译：

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EPR17341 和 A7H6R pan-TRK 免疫组织化学在一系列唾液腺肿瘤中产生高度不同的染色模式

NTRK 重排肿瘤患者现在可以使用抗 TRK 靶向疗法进行治疗，这使得 NTRK 检测对于晚期癌症患者的治疗选择很重要。Pan-TRK 免疫组织化学 (IHC) 可能是该领域的一种有价值的前分子筛选策略。选择一种 IHC 方法或另一种方法需要调查方法间的比较。唾液腺肿瘤中泛TRK阳性肿瘤的高频率使得这些肿瘤特别适合这种技术研究。在这项工作中，我们研究了不同亚型唾液腺肿瘤文件中 2 种泛 TRK IHC 方法（使用 A7H6R 和 EPR17341 克隆）的方法间一致性。在 71 个肿瘤中，使用 EPR17341 和 A7H6R 克隆分别在 23 和 18 例中被诊断为 pan-TRK IHC 阳性（即 H 评分≥5），在阳性/阴性结果方面具有良好的方法间一致性（κ，0.70），但考虑到 H 分数值本身（类内相关系数为 0.5399），只有中等一致性。除了染色强度和染色细胞的百分比之外，还观察到两个克隆之间阳性病例染色的细胞位置和类型之间的主要差异。我们系列中的单个 NTRK 重排病例（即 NTRK3 重排的唾液分泌癌）对 2 个泛 TRK 抗体呈阳性。包括分子证明的 NTRK 重排肿瘤在内的未来研究仍需进一步研究和比较不同泛 TRK 克隆在 NTRK 重排癌症筛查中的表现，但现在很明显 A7H6R 和 EPR17341 克隆的染色模式并不完全相同.