Lee Seung Eun, Park Ha Young, Lim So Dug, Han Hye Seung, Yoo Young Bum, Kim Wan Seop
Department of Pathology, Konkuk University School of Medicine, Seoul, Korea.
Department of Pathology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
J Breast Cancer. 2020 Jun;23(3):303-313. doi: 10.4048/jbc.2020.23.e37.
Triple-negative breast cancer (TNBC) represents a major clinical challenge due to its aggressive and metastatic behavior and the lack of available targeted therapies. Therefore, therapeutic strategies are needed to improve TNBC patient management. Recently, atezolizumab and nab-paclitaxel chemotherapy has been approved by the Food and Drug Administration for the first-line treatment of patients with locally advanced and metastatic TNBC. The programmed death-ligand 1 (PD-L1) immunohistochemical SP142 assay was also approved as a companion diagnostic device for selecting TNBC patients for atezolizumab treatment. This study aimed to evaluate and compare the analytical performance of the PD-L1 22C3/SP263 assays in comparison with the SP142 assay for ≥ 1% immune cells (ICs).
Immunohistochemical expression for the PD-L1 22C3/SP263 assays, in comparison with the SP142 assay, was analyzed for the ≥ 1% ICs in 95 TNBCs.
At the 1% cut-off value, the proportions of positive cases were 52.6% for the SP142 assay in infiltrating ICs and 50.5% and 52.6% for the 22C3 and SP263 assays in tumor cells, respectively. The PD-L1 SP263 assay had the highest while the PD-L1 22C3 assay had the lowest total positive expression rate at all cut-off values. The concordance rate between the assays was highest at a 1% cut-off value and decreased when the cut-off value increased. The concordance rate between the SP142 and SP263 assays at 1% cut-off was high, while in comparison, the concordance rate between the SP142 and 22C3 assays at 1% cut-off was relatively lower.
This study demonstrates that although the 22C3 assay at a 1% cut-off value compared with the PD-L1 SP142 assay at the clinically relevant cut-off shows comparable but not interchangeable analytical performance, the analytical performance of the SP263 assay at a 1% cut-off value shows interchangeable performance with the PD-L1 SP142 assay at the clinically relevant cut-off.
三阴性乳腺癌（TNBC）因其侵袭性和转移行为以及缺乏可用的靶向治疗方法，成为一项重大的临床挑战。因此，需要治疗策略来改善TNBC患者的管理。最近，阿特珠单抗和白蛋白结合型紫杉醇化疗已被美国食品药品监督管理局批准用于局部晚期和转移性TNBC患者的一线治疗。程序性死亡配体1（PD-L1）免疫组织化学SP142检测也被批准作为一种伴随诊断设备，用于选择适合接受阿特珠单抗治疗的TNBC患者。本研究旨在评估和比较PD-L1 22C3/SP263检测与SP142检测对于≥1%免疫细胞（ICs）的分析性能。
对95例TNBC中≥1%的ICs分析PD-L1 22C3/SP263检测与SP142检测的免疫组织化学表达情况。
在1%的临界值时，浸润ICs中SP142检测的阳性病例比例为52.6%，肿瘤细胞中22C3和SP263检测的阳性病例比例分别为50.5%和52.6%。在所有临界值下，PD-L1 SP263检测的总阳性表达率最高，而PD-L1 22C3检测的总阳性表达率最低。各检测之间的一致性率在1%临界值时最高，随着临界值增加而降低。SP142和SP263检测在1%临界值时的一致性率较高，相比之下，SP142和22C3检测在1%临界值时的一致性率相对较低。
本研究表明，虽然1%临界值的22C3检测与临床相关临界值的PD-L1 SP142检测相比，显示出可比但不可互换的分析性能，但1%临界值的SP263检测的分析性能与临床相关临界值的PD-L1 SP142检测显示出可互换的性能。
