PD-L1 and HER2 expression in gastric adenocarcinoma and their prognostic significance

Background: The upregulation of programmed death-ligand 1 (PD-L1) and epidermal growth factor re-ceptor 2 (HER2) may play a role in gastric adenocarcinoma (GAC).Aim: To study PD-L1 and HER-2 expression and prognosis in GAC.Methods: PD-L1 and HER2 expression was determined in tumor tissues of 75 patients with GAC. The correlations between PD-L1, HER2 expression, and clinicopathological factors were analyzed.Results: The positive expression rate for PD-L1 was 57.3% (43/75) and the HER2 over-expression rate was 17.3% (13/75). PD-L1 expression negatively correlated with the grade of GAC differentiation (r = -0.26, P < 0.05). Approximately 85% of HER2-positive GACs were found to be PD-L1-positive and PD-L1 expression positively correlated with HER2 overexpression. The TNM stage and combined HER2 and PD -L1 expression were independent prognostic factors affecting the survival of patients with GAC. The me-dian overall survival and recurrence-free survival of groups I (HER2 overexpression and PD-L1 positive), II (HER2 overexpression and PD-L1 negative), III (No HER2 overexpression and PD-L1 positive) and IV (No HER2 overexpression and PD-L1 negative) were (47 (17-77), 15 (0-4 4), 81 (62-101), and 78 (60-98) months, respectively.Conclusion: PD-L1 expression is upregulated in more than half of patients with GAC. Anti-PD-L1 treat-ment combined with anti-HER2 therapy may benefit patients with locally advanced GAC with HER2 over -expression.(c) 2022 The Authors. Published by Elsevier Ltd on behalf of Editrice Gastroenterologica Italiana S.r.l. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )