Prognostic role of ATM in gastric cancer: A systematic review and meta-analysis.

e16342 Background: Gastric adenocarcinoma remains one of the primary causes of cancer-related mortality worldwide. There is conflicting evidence about the Ataxia-Telangiectasia Mutated (ATM) protein's function as a predictive biomarker in gastric cancer, despite the fact that it is crucial for DNA damage repair and genomic stability. Methods: In accordance with PRISMA criteria and PROSPERO registration (CRD20251035762), we performed a systematic review and meta-analysis of cohort studies up to May 2025. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were computed to evaluate the impact of ATM protein expression on survival outcomes, including overall survival (OS), disease-free survival (DFS), and disease-specific survival (DSS). Results: A meta-analysis of 9 trials including 2,316 patients indicated that higher levels of ATM expression are substantially linked to better overall survival (HR = 1.87, 95% CI: 1.04-3.39, p = 0.04). While the overall pooled disease-free survival (DFS) was not statistically significant (p = 0.18), subgroup analysis of multivariate models indicated a significant correlation between low ATM expression and poor DFS (HR = 3.27, 95% CI: 1.67–6.42, p = 0.0006). Qualitative synthesis further validated a significant connection between ATM mRNA levels and protein expression. Conclusions: ATM expression is a crucial prognostic marker in gastric cancer, where low expression is associated with reduced survival and an elevated risk of recurrence. These results endorse the utilization of ATM as a biomarker for risk assessment and individualized treatment planning.