Since the 2015 WHO classification was introduced into clinical practice, immunohistochemistry (IHC) has figured prominently in lung cancer diagnosis. In addition to distinction of small cell versus non-small cell carcinoma, patients' treatment of choice is directly linked to histologic subtypes of non-small cell carcinoma, which pertains to IHC results, particularly for poorly differentiated tumors. The use of IHC has improved diagnostic accuracy in the classification of lung carcinoma, but the interpretation of IHC results remains challenging in some instances. Also, pathologists must be aware of many interpretation pitfalls, and the use of IHC should be efficient to spare the tissue for molecular testing. The International Association for the Study of Lung Cancer Pathology Committee received questions on practical application and interpretation of IHC in lung cancer diagnosis. After discussions in several International Association for the Study of Lung Cancer Pathology Committee meetings, the issues and caveats were summarized in terms of 11 key questions covering common and important diagnostic situations in a daily clinical practice with some relevant challenging queries. The questions cover topics such as the best IHC markers for distinguishing NSCLC subtypes, differences in thyroid transcription factor 1 clones, and the utility of IHC in diagnosing uncommon subtypes of lung cancer and distinguishing primary from metastatic tumors. This article provides answers and explanations for the key questions about the use of IHC in diagnosis of lung carcinoma, representing viewpoints of experts in thoracic pathology that should assist the community in the appropriate use of IHC in diagnostic pathology.

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肺癌诊断免疫组织化学的最佳实践建议


自 2015 年 WHO 分类引入临床实践以来，免疫组织化学 (IHC) 在肺癌诊断中发挥着重要作用。除了小细胞癌与非小细胞癌的区别之外，患者的治疗选择还与非小细胞癌的组织学亚型直接相关，这与 IHC 结果有关，特别是对于分化差的肿瘤。 IHC 的使用提高了肺癌分类的诊断准确性，但在某些情况下 IHC 结果的解释仍然具有挑战性。此外，病理学家必须意识到许多解释陷阱，并且 IHC 的使用应该能够有效地保留组织进行分子检测。国际肺癌病理学研究协会委员会收到了有关 IHC 在肺癌诊断中的实际应用和解释的问题。经过国际肺癌病理学研究协会多次会议的讨论，问题和注意事项总结为 11 个关键问题，涵盖日常临床实践中常见和重要的诊断情况以及一些相关的挑战性问题。这些问题涵盖的主题包括区分 NSCLC 亚型的最佳 IHC 标记、甲状腺转录因子 1 克隆的差异，以及 IHC 在诊断罕见肺癌亚型和区分原发性肿瘤和转移性肿瘤中的效用。本文对使用 IHC 诊断肺癌的关键问题进行了解答和解释，代表了胸部病理学专家的观点，应有助于社区在诊断病理学中正确使用 IHC。