Department of Pathology and Division of Diagnostic Pathology, Kansai Medical University, Osaka, Japan.
Department of Surgery, Kansai Medical University, Osaka, Japan.
PLoS One. 2021 Sep 24;16(9):e0257860. doi: 10.1371/journal.pone.0257860. eCollection 2021.
Triple-negative breast cancer (TNBC) is the most aggressive type of breast cancer. A recent study demonstrated the efficacy of anti-PD-L1 (anti-programmed death ligand-1) immunotherapy in patients with TNBC. However, the identification of TNBC patients who may benefit from immunotherapy is a critical issue. Several assays have been used to evaluate PD-L1 expression, and a few studies comparing PD-L1 expression using various primary antibodies in TNBC tissues have been reported. However, the expression profiles of the PD-L1 using the 73-10 assay have not yet been analyzed in TNBC tissues.
We analyzed the PD-L1 immunohistochemical profiles of 62 women with TNBC using the 73-10, SP142 (companion diagnostic for atezolizumab), and E1L3N assays. PD-L1 expression on immune cells (ICs) and tumor cells (TCs) was also evaluated, and PD-L1 positivity was defined as a PD-L1-expressing ICs or TCs ≥ 1%.
The expression rates of PD-L1 were 79.0%, 67.7%, and 46.8% on ICs, and 17.7%, 6.5%, and 12.9% on TCs using the 73-10, SP142, and E1L3N assays, respectively. The concordance rates between the 73-10 and SP142 assays were 85.5% (on ICs) and 88.7% (on TCs), respectively, and substantial agreement on ICs (coefficient 0.634) and moderate agreement (coefficient 0.485) on TCs were noted. Sample age and tumor diameter did not influence the ratio of PD-L1 expression among the assays.
The positive rate on ICs and TCs of the 73-10 assay was higher than that of the SP 142 and E1L3N assays. Although substantial agreement on ICs and moderate agreement on TCs between the 73-10 and SP142 assays was noted in the present cohort, further studies are needed to clarify the PD-L1 expression status using various primary antibodies in a larger patient population. This would lead to the establishment of an effective evaluation method to assess the predictive value of anti-PD-L1 immunotherapy.
三阴性乳腺癌（TNBC）是最具侵袭性的乳腺癌类型。最近的一项研究表明，抗 PD-L1（程序性死亡配体 1）免疫疗法对 TNBC 患者有效。然而，确定可能从免疫疗法中获益的 TNBC 患者是一个关键问题。已经使用了几种检测方法来评估 PD-L1 的表达，并且已经报道了一些使用 TNBC 组织中的各种主要抗体比较 PD-L1 表达的研究。然而，73-10 检测中 PD-L1 的表达谱尚未在 TNBC 组织中进行分析。
我们使用 73-10、SP142（atezolizumab 的伴随诊断试剂）和 E1L3N 检测分析了 62 名 TNBC 女性的 PD-L1 免疫组化特征。还评估了 PD-L1 在免疫细胞（ICs）和肿瘤细胞（TCs）上的表达，将 PD-L1 阳性定义为表达 PD-L1 的 ICs 或 TCs≥1%。
使用 73-10、SP142 和 E1L3N 检测，ICs 上 PD-L1 的表达率分别为 79.0%、67.7%和 46.8%，TCs 上 PD-L1 的表达率分别为 17.7%、6.5%和 12.9%。73-10 检测与 SP142 检测的一致性率分别为 85.5%（ICs）和 88.7%（TCs），ICs 上的强一致性（系数 0.634）和 TCs 上的中度一致性（系数 0.485）。样本年龄和肿瘤直径不影响检测之间 PD-L1 表达的比值。
73-10 检测的 ICs 和 TCs 的阳性率高于 SP142 和 E1L3N 检测。虽然在本队列中，73-10 检测与 SP142 检测在 ICs 上具有强一致性，在 TCs 上具有中度一致性，但需要进一步研究在更大的患者人群中使用各种主要抗体来阐明 PD-L1 的表达状态。这将导致建立一种有效的评估方法来评估抗 PD-L1 免疫疗法的预测价值。
