title: PD-L1 expression in human cancers and its association with clinical outcomes.
abstract: PD-L1 is an immunoinhibitory molecule that suppresses the activation of T cells, leading to the progression of tumors. Overexpression of PD-L1 in cancers such as gastric cancer, hepatocellular carcinoma, renal cell carcinoma, esophageal cancer, pancreatic cancer, ovarian cancer, and bladder cancer is associated with poor clinical outcomes. In contrast, PD-L1 expression correlates with better clinical outcomes in breast cancer and merkel cell carcinoma. The prognostic value of PD-L1 expression in lung cancer, colorectal cancer, and melanoma is controversial. Blocking antibodies that target PD-1 and PD-L1 have achieved remarkable response rates in cancer patients who have PD-L1-overexpressing tumors. However, using PD-L1 as an exclusive predictive biomarker for cancer immunotherapy is questionable due to the low accuracy of PD-L1 immunohistochemistry staining. Factors that affect the accuracy of PD-L1 immunohistochemistry staining are as follows. First, antibodies used in different studies have different sensitivity. Second, in different studies, the cut-off value of PD-L1 staining positivity is different. Third, PD-L1 expression in tumors is not uniform, and sampling time and location may affect the results of PD-L1 staining. Therefore, better understanding of tumor microenvironment and use of other biomarkers such as gene marker and combined index are necessary to better identify patients who will benefit from PD-1/PD-L1 checkpoint blockade therapy.
authors: School of Medicine and Life Sciences, University of Jinan - Shandong Academy of Medical Sciences; Department of Radiation Oncology, Shandong Cancer Hospital and Institute.
authors: Xin
authors: X
authors: Wang
authors: Department of Radiation Oncology, Shandong Cancer Hospital and Institute; School of Medicine, Shandong University, Jinan, People's Republic of China.
authors: Feifei
authors: F
authors: Teng
authors: Department of Radiation Oncology, Shandong Cancer Hospital and Institute.
authors: Li
authors: L
authors: Kong
authors: Department of Radiation Oncology, Shandong Cancer Hospital and Institute.
authors: Jinming
authors: J
authors: Yu
keywords: PD-L1; checkpoint blockade; clinical outcome; immunotherapy; prognostic value