AUTHOR=Azevedo Jéssica Gonçalves , Cortez Beatriz de Araujo , Rego Maria Aparecida do Carmo , Berlinski Felipe , Ferreira Dominihemberg , Carreira dos Santos Angélica , Almeida Ana Beatriz Machado De , Batista Paula de Mendonça , Marcelino Cicera Pimenta , Munari Fernanda Franco , Santana Iara Viana Vidigal , da Silva Vinicius Duval , Ribeiro Guilherme , Berardinelli Gustavo Noriz , Burgardt Diego , Wohnrath Durval R. , Reis Rui Manuel 

TITLE=Expression of programmed cell death ligand 1 protein and other biomarkers in patients with gastric cancer and gastroesophageal junction cancer: a retrospective single centre study in Brazil

JOURNAL=Frontiers in Oncology

VOLUME=Volume 15 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2025.1623264

DOI=10.3389/fonc.2025.1623264

ISSN=2234-943X

ABSTRACT=BackgroundProgrammed cell death ligand 1 (PD-L1) is a key prognostic biomarker that can predict response to immunotherapies in patients with gastric cancer (GC) and gastroesophageal junction cancer (GEJC). However, there is a lack of real-world data on the distribution of PD-L1 and other prognostic biomarkers among patients with GC and GEJC in Brazil.ObjectivesTo analyze PD-L1 expression, the microsatellite instability (MSI) and human epidermal growth factor receptor 2 (HER-2) status among patients with GC and GEJC in a Brazilian cancer hospital and to evaluate the association between PD-L1 expression and other biomarkers and clinicopathological parameters.MethodsThis observational, retrospective study was conducted between March 2019 and May 2019 at the Barretos Cancer Hospital in Brazil. The levels of PD-L1 expression and other biomarkers were analyzed for patients whose formalin-fixed paraffin-embedded tumor tissue samples were preserved at the hospital. PD-L1 expression was measured by the immunohistochemical (IHC) method. MSI was determined by molecular assays, whereas IHC and fluorescence in situ hybridization (FISH) assays were conducted to evaluate HER-2 expression. The association between PD-L1 expression, MSI, HER-2-positivity, and clinicopathological parameters was determined using a chi-square test.ResultsA total of 162 patients were included in the study. Most of the patients were male (65.4%), with a mean age of 61 years. PD-L1 expression (CPS ≥1) was observed in 49.4% of patients (n = 80) of patients, whereas MSI-high and HER-2 expression were reported in 12.3% (n = 20) and 8.0% (n = 13), respectively. PD-L1 expression was significantly associated with older age and MSI.ConclusionA high prevalence of PD-L1 expression was observed among patients with GC and GEJC, but HER-2-positivity was lower than global prevalence. PD-L1 expression was associated with MSI-high status. The study outcomes can be used for the selection of appropriate therapies for patients with GC and GEJC in Brazil.