amplification (amp) represents a promising therapeutic target in non–small cell lung cancer, but no consensus has been established to identify amp-dependent tumors that could potentially benefit from MET inhibitors. In this study, an analysis of amplification/overexpression status was performed in a retrospectively recruited cohort comprising 231 patients with non–small cell lung cancer from Shanghai Chest Hospital (SCH cohort) using 3 methods: fluorescence in situ hybridization (FISH), hybrid capture-based next-generation sequencing, and immunohistochemistry for c-MET and phospho-MET. The SCH cohort included 130 cases known to be amp positive by FISH and 101 negative controls. The clinical relevance of these approaches in predicting the efficacy of MET inhibitors was evaluated. Additionally, next-generation sequencing data from another 2 cohorts including 22,010 lung cancer cases were utilized to examine the biological characteristics of different amp subtypes. Of the 231 cases, 145 showed amplification/overexpression using at least 1 method, whereas only half of them could be identified by all 3 methods. amp can occur as focal amplification or polysomy. Our study revealed that the inconsistency between next-generation sequencing and FISH primarily occurred in the polysomy subtype. Further investigations indicated that compared with polysomy, focal amplification correlated with fewer co-occurring driver mutations, higher protein expressions of c-MET and phospho-MET, and higher incidence in acquired resistance than in de novo setting. Moreover, patients with focal amplification presented a more robust response to MET inhibitors compared with those with polysomy. Notably, a strong correlation was observed between focal amplification and programmed cell death ligand-1 expression, indicating potential therapeutic implications with combined MET inhibitor and immunotherapy for patients with both alterations. Our findings provide insights into the molecular complexity and clinical relevance of amp in lung cancer, highlighting the role of focal amplification as an oncogenic driver and its feasibility as a primary biomarker to further investigate the clinical activity of MET inhibitors in future studies.

中文翻译：

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揭示 MET 局灶扩增在肺癌中的意义：综合 NGS、FISH 和 IHC 研究

放大 (amp) 是非小细胞肺癌的一个有前景的治疗靶点，但尚未达成共识来识别 amp 依赖性肿瘤是否可能受益于 MET 抑制剂。本研究采用荧光原位杂交（FISH）、杂交捕获等 3 种方法，对上海胸科医院回顾性招募的 231 例非小细胞肺癌患者（SCH 队列）进行扩增/过表达状态分析。基于 c-MET 和磷酸化 MET 的下一代测序和免疫组织化学。 SCH 队列包括 130 例 FISH 检测呈阳性的病例和 101 例阴性对照。评估了这些方法在预测 MET 抑制剂功效方面的临床相关性。此外，还利用来自另外 2 个队列（包括 22,010 个肺癌病例）的下一代测序数据来检查不同 amp 亚型的生物学特征。在 231 个病例中，145 个病例至少使用 1 种方法显示扩增/过表达，而其中只有一半可以通过所有 3 种方法进行鉴定。 amp 可以以局部放大或多体性的形式发生。我们的研究表明，下一代测序和 FISH 之间的不一致主要发生在多体亚型中。进一步的研究表明，与多体性相比，局灶性扩增与较少的共存驱动突变、较高的 c-MET 和磷酸化 MET 蛋白表达以及较高的获得性耐药发生率相关。此外，与多体性患者相比，局灶性扩增患者对 MET 抑制剂表现出更强的反应。值得注意的是，在局灶性扩增和程序性细胞死亡配体 1 表达之间观察到很强的相关性，表明 MET 抑制剂和免疫疗法联合治疗对具有这两种改变的患者具有潜在的治疗意义。我们的研究结果提供了对 amp 在肺癌中的分子复杂性和临床相关性的见解，强调了局灶放大作为致癌驱动因素的作用及其作为主要生物标志物的可行性，以在未来的研究中进一步研究 MET 抑制剂的临床活性。