Division of Pathology, IEO, European Institute of Oncology IRCCS, Milan, Italy; Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy.
Division of Pathology, IEO, European Institute of Oncology IRCCS, Milan, Italy.
Crit Rev Oncol Hematol. 2023 Oct;190:104103. doi: 10.1016/j.critrevonc.2023.104103. Epub 2023 Aug 16.
Pembrolizumab has received approval as a first-line treatment for unresectable/metastatic triple-negative breast cancer (mTNBC) with a PD-L1 combined positive score (CPS) of ≥ 10. However, assessing CPS in mTNBC poses challenges. Firstly, it represents a novel analysis for breast pathologists. Secondly, the heterogeneity of PD-L1 expression in mTNBC further complicates the assessment. Lastly, the lack of standardized assays and staining platforms adds to the complexity. In KEYNOTE trials, PD-L1 expression was evaluated using the IHC 22C3 pharmDx kit as a companion diagnostic test. However, both the 22C3 pharmDx and VENTANA PD-L1 (SP263) assays are validated for CPS assessment. Consequently, assay-platform choice, staining conditions, and scoring methods can significantly impact the testing outcomes. This consensus paper aims to discuss the intricacies of PD-L1 CPS testing in mTNBC and provide practical recommendations for pathologists. Additionally, we present findings from a nationwide Italian survey elucidating the state-of-the-art in PD-L1 CPS testing in mTNBC.
帕博利珠单抗已被批准用于治疗不可切除/转移性三阴性乳腺癌（mTNBC），其 PD-L1 综合阳性评分（CPS）≥10。然而，评估 mTNBC 中的 CPS 存在挑战。首先，它代表了乳腺病理学家的一项新分析。其次，mTNBC 中 PD-L1 表达的异质性进一步使评估复杂化。最后，缺乏标准化的检测和染色平台增加了复杂性。在 KEYNOTE 试验中，使用 IHC 22C3 pharmDx 试剂盒评估 PD-L1 表达，作为伴随诊断检测。然而，22C3 pharmDx 和 VENTANA PD-L1（SP263）检测均经过 CPS 评估验证。因此，检测平台的选择、染色条件和评分方法可能会显著影响检测结果。本共识文件旨在讨论 mTNBC 中 PD-L1 CPS 检测的复杂性，并为病理学家提供实用建议。此外，我们还介绍了一项全国性意大利调查的结果，阐明了 mTNBC 中 PD-L1 CPS 检测的最新情况。
