Departments of Molecular and Anatomic Pathology, Pathology and Laboratory Medicine Institute, Cleveland, OH, USA.
J Mol Diagn. 2013 May;15(3):341-6. doi: 10.1016/j.jmoldx.2013.01.004. Epub 2013 Mar 13.
ALK gene rearrangements in advanced non-small cell lung carcinomas (NSCLC) are an indication for targeted therapy with crizotinib. Fluorescence in situ hybridization (FISH) using a recently approved companion in vitro diagnostic class FISH system commonly assesses ALK status. More accessible IHC is challenged by low expression of ALK-fusion transcripts in NSCLC. We compared ultrasensitive automated IHC with FISH for detecting ALK status on 318 FFPE and 40 matched ThinPrep specimens from 296 patients with advanced NSCLC. IHC was concordant with FFPE-FISH on 229 of 231 dual-informative samples (31 positive and 198 negative) and with ThinPrep-FISH on 34 of 34 samples (5 positive and 29 negative). Two cases with negative IHC and borderline-positive FFPE-FISH (15% and 18%, respectively) were reclassified as concordant based on negative matched ThinPrep-FISH and clinical data consistent with ALK-negative status. Overall, after including ThinPrep-FISH and amending the false-positive FFPE-FISH results, IHC demonstrated 100% sensitivity and specificity (95% CI, 0.86 to 1.00 and 0.97 to 1.00, respectively) for ALK detection on 249 dual-informative NSCLC samples. IHC was informative on significantly more samples than FFPE-FISH, revealing additional ALK-positive cases. The high concordance with FISH warrants IHC's routine use as the initial component of an algorithmic approach to clinical ALK testing in NSCLC, followed by reflex FISH confirmation of IHC-positive cases.
ALK 基因重排在晚期非小细胞肺癌（NSCLC）中是使用克唑替尼进行靶向治疗的指征。使用最近批准的体外诊断类 FISH 系统进行荧光原位杂交（FISH）通常评估 ALK 状态。免疫组织化学（IHC）更易于获得，但 NSCLC 中 ALK 融合转录本的低表达带来了挑战。我们比较了超敏自动化 IHC 和 FISH 用于检测 296 例晚期 NSCLC 患者的 318 例 FFPE 和 40 例配对 ThinPrep 标本中的 ALK 状态。IHC 在 229 例双信息样本（31 例阳性和 198 例阴性）上与 FFPE-FISH 一致，在 34 例 ThinPrep-FISH 样本上与 ThinPrep-FISH 一致（5 例阳性和 29 例阴性）。2 例 IHC 阴性且 FFPE-FISH 边界阳性（分别为 15%和 18%）的病例根据阴性匹配的 ThinPrep-FISH 和临床数据重新分类为一致，这些数据与 ALK 阴性状态一致。总体而言，在包括 ThinPrep-FISH 并修正了假阳性 FFPE-FISH 结果后，IHC 在 249 例双信息 NSCLC 样本中显示出 100%的 ALK 检测灵敏度和特异性（95%CI 分别为 0.86 至 1.00 和 0.97 至 1.00）。IHC 比 FFPE-FISH 更能提供信息，揭示了更多的 ALK 阳性病例。与 FISH 的高度一致性证明了 IHC 作为 NSCLC 中临床 ALK 检测算法方法初始组件的常规使用的合理性，随后对 IHC 阳性病例进行 FISH 确认。
