We observed a significant reduction in CDH1 mutations in CCNE1-amplified gastric adenocarcinoma versus nonamplified gastric adenocarcinoma (2.9% vs. 16.4%, P = 0.0002) as well as a reduction in CLDN18:ARHGAP fusions (0% vs. 6.8%); however, the frequency of RHOA mutations were similar (Supplementary Fig. S2C). Here, CLDN18 is linked to gastric adenocarcinoma.