The clinical significance of ARID1A mutations in gastric cancer patients

Background: ARID1A is a key component of the SWI/SNF chromatin remodeling complex, which has been identified in various cancers. Loss of ARID1A expression is correlated with poor prognosis in gastric cancer (GC); however, the clinical relevance of ARID1A mutations in GC has not yet been reported. Materials and Methods: A total of 518 GC patients receiving gastrectomy were enrolled. The analysis of 13 mutations of the ARID1A gene using mass spectrometric single-nucleotide polymorphism genotyping technology was conducted. The clinicopathological features of GC with and without ARID1A mutations were compared. Results: Among the 518 GC patients, 59 (11.4%) had ARID1A mutations. For diffuse-type GC, patients with ARID1A-mutated tumors were older and had fewer poorly differentiated tumors, fewer incidence of Epstein-Barr virus infection, a higher likelihood of ARID1A expression loss, more microsatellite instability-high tumors, a lower prevalence of peritoneal recurrence, and better survival rates than those with ARID1A nonmutant tumors. For intestinal-type GC, patients with ARID1A-mutant tumors had more PI3K/AKT pathway genetic mutations than patients with ARID1A nonmutant tumors. Multivariate analysis showed that ARID1A mutations are an independent prognostic factor in diffuse-type GC. Conclusion: ARID1A mutations are associated with a better prognosis in diffuse-type GC.