ARID1A and gastric adenocarcinoma: In total, 223 of 434 STAD samples (52%) harbored pathogenetic alterations in at least one SWI/SNF subunit, including ARID1A (118, 27%), SMARCA2 (40, 9%), ARID2 (38, 9%), ARID1B (34, 8%), PBRM1 (32, 7%), SMARCA4 (29, 7%) and BCL11A (25, 6%) (Fig 4A).