Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Clin Lung Cancer. 2019 Jul;20(4):258-262.e1. doi: 10.1016/j.cllc.2019.02.012. Epub 2019 Feb 27.
The immunohistochemical analysis of programmed cell death ligand 1 (PD-L1) expression in tumor tissue of non-small-cell lung cancer patients has now been integrated in the diagnostic workup. Analysis is commonly done on small tissue biopsy samples representing a minimal fraction of the whole tumor. The aim of the study was to evaluate the correlation of PD-L1 expression on biopsy specimens with corresponding resection specimens.
In total, 58 consecutive cases with preoperative biopsy and resected tumor specimens were selected. From each resection specimen 2 tumor cores were compiled into a tissue microarray (TMA). Immunohistochemical staining with the antibody SP263 was performed on biopsy specimens, resection specimens (whole sections), as well as on the TMA.
The proportion of PD-L1-positive stainings were comparable between the resection specimens (48% and 19%), the biopsies (43% and 17%), and the TMAs (47% and 14%), using cutoffs of 1% and 50%, respectively (P > .39 all comparisons). When the resection specimens were considered as reference, PD-L1 status differed in 16%/5% for biopsies and in 9%/9% for TMAs (1%/50% cutoff). The sensitivity of the biopsy analysis was 79%/82% and the specificity was 90%/98% at the 1%/50% cutoff. The Cohens κ value for the agreement between biopsy and tumor. was 0.70 at the 1% cutoff and 0.83 at the 50% cutoff.
The results indicate a moderate concordance between the analysis of biopsy and whole tumor tissue, resulting in misclassification of samples in particular when the lower 1% cutoff was used. Clinicians should be aware of this uncertainty when interpreting PD-L1 reports for treatment decisions.
程序性细胞死亡配体 1（PD-L1）在非小细胞肺癌患者肿瘤组织中的免疫组织化学分析现已纳入诊断评估。分析通常在代表整个肿瘤一小部分的小组织活检样本上进行。本研究的目的是评估活检标本中 PD-L1 表达与相应切除标本的相关性。
共选择了 58 例有术前活检和切除肿瘤标本的连续病例。从每个切除标本中编制 2 个肿瘤核心纳入组织微阵列（TMA）。使用抗体 SP263 对活检标本、切除标本（全切片）以及 TMA 进行免疫组织化学染色。
使用 1%和 50%的截断值，分别比较切除标本（48%和 19%）、活检标本（43%和 17%）和 TMA（47%和 14%）中 PD-L1 阳性染色的比例，差异无统计学意义（所有比较 P >.39）。当将切除标本作为参考时，活检和 TMA 的 PD-L1 状态分别有 16%/5%和 9%/9%不同（1%/50%截断值）。活检分析的敏感性分别为 79%/82%，特异性分别为 90%/98%，在 1%/50%的截断值。活检和肿瘤的 Cohen's κ 值在 1%的截断值时为 0.70，在 50%的截断值时为 0.83。
结果表明，活检和整个肿瘤组织分析之间存在中度一致性，特别是当使用较低的 1%截断值时，会导致样本分类错误。临床医生在解释 PD-L1 报告以做出治疗决策时，应注意这种不确定性。
