Purpose We provide a comparison between 22C3 pharmDx and SP263 assay, for evaluating programmed death ligand 1 (PD-L1) expression in advanced gastric cancer (GC) patients.Materials and Methods The PD-L1 immunohistochemistry by 22C3 pharmDx and SP263 assays was performed in the center of the tumor (CT) and invasive margin (IM) in 379 GC tissues using tissue microarrays and interpreted as combined positive score (CPS) and tumor proportion score (TPS). Of the total samples, 55 samples were independently reviewed by five pathologists.Results The two assays showed a high correlation in both the CPS and TPS. At a CPS ≥ 1 cut-off, 219 (57.8%) and 231 (60.9%) GCs were positive for PD-L1 with the 22C3 and SP263 assays, and at ≥ 10 cut-off, 37 (9.8%) and 36 (9.5%) GCs were positive, respectively. The overall percent agreement (OPA) was greater than 90% with CPS ≥ 1 and ≥ 10 cut-offs, and TPS ≥ 1% and ≥ 10% cut-offs. There was higher OPA between the two assays with a CPS cut-off ≥ 10 (99.2%) than ≥ 1 (94.7%). The percent agreement between the CT and IM was higher with a CPS cut-off ≥ 10 (92.9%) than ≥ 1 (77.6%). Patient with positive expression at CPS ≥ 5 cut-off had a significantly better outcomes in both assays. Interobserver variability among five pathologists was higher than the assay variability.Conclusion Two assays for PD-L1 expression in GC showed high agreement. These results provide guidance for selecting eligible patients with GC for pembrolizumab treatment.

We sought to determine the clinicopathological significance of PD-1, LAG3, and TIM3 in gastric cancer (GC) by examining their expression and immune context. Immunohistochemistry (IHC) for PD-1, TIM3, LAG3, and tumor-infiltrating immune cell (TIIC) markers was performed in 385 stage II/III GCs. Epstein-Barr virus (EBV) and microsatellite stability (MSI) testing were performed for molecular classification. Chromogenic multiplex IHC (mIHC) for PD1, TIM3, LAG3, CD3, CD8, FOXP3, CD68, and cytokeratin was performed in 58 of the total samples. PD-1, LAG3, and TIM3 expression in TIICs was observed in 91 (23.6%), 193 (50.1%), and 257 (66.8%) GCs by single IHC, respectively. The expression was associated with EBV + and MSI-H molecular subtypes (p ≤ 0.001). A positive expression of LAG3 in the invasive margin of the tumor was associated with better prognosis in univariate (p = .020) and multivariate (p = .026) survival analyses. The expression of different immune checkpoint receptors (ICRs) was significantly positively correlated. Dual or triple ICR expression was more frequent in high PD-1 and TIM3 density groups than in low-density groups by mIHC (all p ≤ 0.05). ICRs were mainly expressed in CD3 + CD8 + and CD3 + CD8 − T cells. Fifty-eight GCs were classified into three groups by clustering analysis based on mIHC, and the group with the highest ICR expression in TIICs showed significantly better outcomes in progression-free survival (p = .020). In GC, PD-1, LAG3, and TIM3 expression is positively correlated and associated with better prognosis.Our study provides information for the application of effective immune checkpoint inhibitors against GC.

Background: Recently, molecular classifications of gastric cancer (GC) have been proposed that include TP53 mutations and their functional activity. We aimed to demonstrate the correlation between p53 immunohistochemistry (IHC) and TP53 mutations as well as their clinicopathological significance in GC. Methods: Deep targeted sequencing was performed using surgical or biopsy specimens from 120 patients with GC. IHC for p53 was performed and interpreted as strong, weak, or negative expression. In 18 cases (15.0%) with discrepant TP53 mutation and p53 IHC results, p53 IHC was repeated. Results: Strong expression of p53 was associated with TP53 missense mutations, negative expression with other types of mutations, and weak expression with wild-type TP53 (p < .001). The sensitivity for each category was 90.9%, 79.0%, and 80.9%, and the specificity was 95.4%, 88.1%, and 92.3%, respectively. The TNM stage at initial diagnosis exhibited a significant correlation with both TP53 mutation type (p = .004) and p53 expression status (p = .029). The Kaplan-Meier survival analysis for 109 stage II and III GC cases showed that patients with TP53 missense mutations had worse overall survival than those in the wild-type and other mutation groups (p = .028). Strong expression of p53 was also associated with worse overall survival in comparison to negative and weak expression (p = .035). Conclusions: Results of IHC of the p53 protein may be used as a simple surrogate marker of TP53 mutations. However, negative expression of p53 and other types of mutations of TP53 should be carefully interpreted because of its lower sensitivity and different prognostic implications.

The aim of this study was to determine the clinicopathological significance of programmed cell death ligand 1 (PD-L1) expression in glioblastoma (GBM). In a retrospective cohort of 115 consecutive patients with GBM, PD-L1 expression was determined using immunohistochemistry (IHC). Membranous and fibrillary PD-L1 staining of any intensity in > 5% neoplastic cells and tumour infiltrating immune cells (TIIs) was considered positive staining. In addition, isocitrate dehydrogenase-1 (IDH-1) (R132H) expression and cluster of differentiation 3 (CD3)-positive T-cell infiltration were investigated using IHC. O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation assay and fluorescence in situ hybridization (FISH) for the assessment of 1p/19q deletion were performed. Expression of PD-L1 in tumour cells and TIIs was found in 37 (32.2%) and 6 (5.2%) patients, respectively. Kaplan-Meier analysis indicated that PD-L1 expression in tumour cells was significantly associated with poor overall survival (OS) (P = 0.017), though multivariate Cox analysis did not confirm this association (hazard ratio 1.204; P = 0.615). PD-L1 expression in TIIs did not correlate with the patient prognosis (P = 0.545). In addition, MGMT methylation and IDH-1 (R132H) expression were associated with a better prognosis (P < 0.001 and P = 0.024, respectively). The expression of PD-L1 was associated with CD3-positive T-cell infiltration (P < 0.001), and IDH-1 wild type status (P = 0.008). A deeper insight into PD-L1 expression could help to ensure the success of future immunotherapy in GBM. Our study suggested that PD-L1 target therapy might be beneficial for PD-L1-expressing GBM patients with a poor prognosis.