Characterization of PD-L1 Immunohistochemical Expression in Cell Blocks With Different Specimen Fixation and Processing Methods
Characterization of PD-L1 Immunohistochemical Expression in Cell Blocks With Different Specimen Fixation and Processing Methods
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DOI：
10.1097/pai.0000000000000572
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发表时间：
2019-02-01
影响因子：
1.6
通讯作者：
Chadwick, Barbara E.
中科院分区：
文献类型：
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作者：
Lloyd, Isaac E.;Zhou, Wenhua;Chadwick, Barbara E.
程序性死亡配体1 （PD-L1）免疫组织化学（IHC）的解释标准主要基于福尔马林固定的石蜡包埋组织的数据，尽管细胞学标本，特别是细胞块，通常是唯一或最容易获得的测试组织。然而，与活组织检查标本不同，细胞学样品处理方法可以有显著差异。本研究的目的是评估几个常见的分析前变量对PD-L1 IHC的影响。体外培养两株PD-L1强表达（H441）和不表达（MCF7）的细胞系。采集的细胞分别在PreservCyt、CytoLyt、细胞培养基（RPMI）、生理盐水和福尔马林中收集。细胞块由血浆凝血活素法或celllient自动化系统制备，并按方案用fda批准的28-8 PD-L1抗体染色。PD-L1的表达由3名病理学家手工评分染色强度和定位，并比较不同制备方法的差异。观察到几种免疫组化染色模式：完全膜性，部分膜性，球状和细胞质，有一些重叠。celllient块具有最好的观察者间一致性和细胞形态学，强完全膜性染色比例最高（82%），细胞质和球状染色比例最低（11%）（8%）。与celllient相比，RPMI、生理盐水和福尔马林样品的细胞质和球状染色量增加，而CytoLyt的总体表现最差。细胞块上PD-L1免疫组化的解释对于大多数检查的处理方法是可行的，但可能需要识别某些样品类型中增加的细胞质和球状染色。与其他方法相比，celllient细胞块显示出优越的性能。
Interpretative criteria for programmed death-ligand 1 (PD-L1) immunohistochemistry (IHC) have been largely based on data from formalin-fixed, paraffin-embedded tissues, despite the fact that cytologic specimens, especially cell blocks, are often the only or most readily available tissue for testing. Unlike biopsy specimens, however, cytology sample processing methods can vary markedly. The purpose of this study was to evaluate the effects of several common preanalytic variables on PD-L1 IHC. Two cell lines with strong expression of PD-L1 (H441) and no expression (MCF7) were cultured in vitro. Harvested cells were collected in PreservCyt, CytoLyt, cell culture media (RPMI), saline, and formalin. Cell blocks were prepared by the plasma-thromboplastin method or Cellient automated system and stained with the FDA-approved 28-8 PD-L1 antibody per protocol. PD-L1 expression was scored manually by 3 pathologists for stain intensity and localization and compared across preparation methods. Several IHC staining patterns were observed: complete membranous, partial membranous, globular, and cytoplasmic, with some overlap. Cellient blocks had the best interobserver agreement and cytomorphology, highest proportion of strong complete membranous staining (82%), and least amount of cytoplasmic (11%) and globular staining (8%). RPMI, saline, and formalin samples demonstrated increased amounts of cytoplasmic and globular staining relative to Cellient, while CytoLyt exhibited the poorest performance overall. Interpretation of PD-L1 IHC on cell blocks is feasible for most processing methods examined, but may require recognition of increased cytoplasmic and globular staining in some sample types. Cellient cell blocks demonstrated superior performance compared with other methods.