ObjectiveTo systematically evaluate the expression of programmed cell death receptor 1 (PD-1) and programmed cell death ligand 1 (PD-L1) in esophageal squamous cell carcinoma and its relationship with prognosis.MethodsThe literature from PubMed, EMbase, The Cochrane Library, Web of Science, CNKI and Wanfang data from inception to February 22, 2020 was searched by computer. Data were extracted and the quality of literature was evaluated using RevMan 5.3 software for meta-analysis. Egger's and Begg's tests were used to evaluate publication bias, and Stata 15.1 software was used for sensitivity analysis.Results A total of 16 articles were included, and there were 3 378 patients with esophageal squamous cell carcinoma. The methodological index for nonrandomized studies (MINORS) scores were all 12 points and above. The meta-analysis results showed that the positive expression rates of PD-1 and PD-L1 in tumor cells were 37.8% (190/504) and 41.7% (1 407/3 378), respectively. The positive expression of PD-L1 in tumor immune infiltrating cells was 41.7% (412/987). The overall survival (OS) of the tumor cell with high PD-L1 expression was lower than that with low PD-LI expression (HR=1.30, 95%CI 1.01-1.69, P=0.04). The OS of the tumor immune infiltrating cell with high PD-L1 expression was significantly higher than that with low PD-LI expression (HR=0.65, 95%CI 0.53-0.80, P<0.0001).ConclusionPD-L1 has a high expression rate in esophageal squamous cell carcinoma and is an important factor for the prognosis of esophageal squamous cell carcinoma.
ObjectiveTo summarize the mechanism of action of programmed cell death protein 1 (PD-1)/programmed cell death ligand-1 (PD-L1) inhibitors, the application in breast cancer in recent years and the advances in the study of their bio-markers of effects. MethodRelevant literatures on PD-1/PD-L1 inhibitors and the study in the field of breast cancer were reviewed and summarized.ResultsIn recent years, the monotherapy of immune checkpoint inhibitors represented by PD-1/PD-L1 inhibitors or in combination with other therapies had brought new hope for patients with breast cancer especially triple-negative breast cancer (TNBC). However, only a small number of patients could benefit from breast cancer immunotherapy. The current researchers think that the efficacy of these drugs is related to PD-L1 expression in tumor tissue, tumor mutation burden (TMB), high level of microsatellite instability (MSI-H) and deficient mismatch repair (dMMR).ConclusionBreast cancer can benefit from the immunotherapy of PD-1/PD-L1 inhibitors, but formulating personalized medicine model, finding biomarkers that can predict efficacy and selecting patients with breast cancer who can benefit from it for targeted therapy are the new requirements in the new era of breast cancer immunotherapy.