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Programmed death ligand 1 (PD-L1) protein expression is a proposed predictive biomarker of immunotherapy; thus, identification of the clinicopathological and molecular characteristics associated with PD-L1 expression is important and necessary. We examined PD-L1 immunohistochemical expression and its relationships with the clinicopathological and molecular characteristics of patients with surgically resected nonsmall cell lung carcinoma. PD-L1 expression differed according to the histological subtype. Among 633 patients with adenocarcinoma, 523 (82.6%) had no PD-L1 expression, 78 (12.3%) low expression, and 32 (5.1%) high expression. PD-L1 expression was more common in men (p < 0.001), in smokers (p = 0.002), and in patients with a more advanced stage (p = 0.002), the solid predominant subtype (p < 0.001), no epidermal growth factor receptor(EGFR) mutations (p < 0.001), a high MIB-1 labeling index (p < 0.001), and positive p53 immunohistochemical expression (p < 0.001). In a multivariate logistic regression analysis, the solid predominant subtype (odds ratio [OR] = 4.92, 95% confidence interval [CI]: 2.72-8.89, p < 0.001), no EGFR mutations (OR = 2.27, 95% CI: 1.35-2.7, p = 0.002), a high MIB-1 labeling index (OR = 2.78, 95% CI: 1.72-4.55, p < 0.001), and p53 positivity (OR = 2.13, 95% CI: 1.34-4.36, p = 0.042) were significantly and independently associated with PD-L1 expression. The combination of the solid predominant subtype with a high MIB-1 labeling index was strongly associated with positive expression of PD-L1. In the 193 patients with squamous cell carcinoma, 92 (47.7%) had no PD-L1 expression, 57 (29.5%) low expression, and 44 (22.8%) high expression. There were no significant correlations between PD-L1 expression and the evaluated clinicopathological or molecular characteristics of these patients. These results, indicating associations of PD-L1 with various clinicopathological or molecular characteristics in adenocarcinoma but not squamous cell carcinoma, may be useful for selecting patients with a good response to immune checkpoint inhibitors., (Copyright © 2020 Elsevier Inc. All rights reserved.)

We compared a monoclonal antibody (SV2-61γ) and a polyclonal antibody (Dako HercepTest) in immunohistochemical assessments of human epidermal growth factor receptor 2 (HER2) expression in 73 samples of advanced gastric cancer. Results were scored as 0 to 3+, and equivocal or discordant (SV2-61γ/Dako HercepTest = 0/2+, 0/3+, 1+/3+ or 2+/3+) cases were subjected to fluorescence in situ hybridization (FISH) analysis. The frequencies of HER2 scores of 2+ or 3+ were 15.1% (11/73) using SV2-61γ and 38.4% (28/73) using Dako HercepTest. All of the equivocal or discordant cases with a HER2 score of 3+ using Dako HercepTest exhibited amplification of the HER2 gene regardless of the HER2 score determined with SV2-61γ. The results of the HER2 tests differed according to the antibodies used for immunohistochemistry that preceded FISH analysis, being 15.1% (11/73) using SV2-61γ and 23.3% (17/73) using Dako HercepTest. Thus, therapeutic decisions might be markedly influenced by the selection of antibody used in the HER2 test., (© 2012 The Authors. Pathology International © 2012 Japanese Society of Pathology and Blackwell Publishing Asia Pty Ltd.)