Herein, we found that HNF4α-positive non-mucinous adenocarcinomas frequently showed loss of SMARCA4 (3/15, 20%), much more frequently than in mucinous, enteric, and colloid adenocarcinomas (0/18, 0%), and HNF4α-negative non-mucinous adenocarcinomas (3/208, 1.4%). The gene discussed is SMARCA4; the disease is mucinous adenocarcinoma.