Oh Kei Shing, Mahalingam Meera
Tutor, Department of Pathology, St. George's University, Grenada, West Indies.
Professor of Dermatology, Tufts University School of Medicine, Boston, MA.
Am J Dermatopathol. 2019 Aug;41(8):539-565. doi: 10.1097/DAD.0000000000001287.
PD-L1 is a transmembrane glycoprotein with an extracellular as well as an intracellular cytoplasmic domain. Physiologically, it plays a pivotal role in regulating T-cell activation and tolerance. Many tumor cells have exploited this regulatory mechanism by overexpressing PD-L1 in an effort to escape immunologic surveillance. In this review, we parse the literature regarding the prognostic value of tumoral PD-L1 expression before discussing the various methodologies as well as the pearls and pitfalls associated with each for predicting response to anti-PD-1/PD-L1 therapies. Special attention is given to cutaneous entities in which PD-L1 expression has been documented with an emphasis on cutaneous malignancies that have seen the broadest applications of anti-PD-L1/PD-1 therapies. Currently, immunohistochemistry is the method that is most commonly used for detection of PD-L1. However, with the wide array of immunohistochemistry protocols and staining platforms available in the market, there seems to be different cutoffs not just for different entities but also for the same entity. This review is an attempt to address the need for standardization and validation of existing protocols for PD-L1 detection.
程序性死亡受体配体1（PD-L1）是一种跨膜糖蛋白，具有细胞外和细胞内胞质结构域。在生理情况下，它在调节T细胞活化和耐受中起关键作用。许多肿瘤细胞通过过度表达PD-L1利用这种调节机制，以逃避免疫监视。在本综述中，我们在讨论预测抗PD-1/PD-L1治疗反应的各种方法以及每种方法的要点和陷阱之前，先剖析了有关肿瘤PD-L1表达预后价值的文献。特别关注已记录PD-L1表达的皮肤疾病，重点是抗PD-L1/PD-1治疗应用最广泛的皮肤恶性肿瘤。目前，免疫组织化学是最常用于检测PD-L1的方法。然而，鉴于市场上有各种各样的免疫组织化学方案和染色平台，似乎不仅针对不同疾病，而且针对同一疾病都有不同的临界值。本综述旨在满足对现有PD-L1检测方案进行标准化和验证的需求。
