ERBB4 and gastric cancer: While ERBB2 and ERBB3 are both molecular targets of FDA-approved gastric cancer therapies and are known TCGA gastric cancer drivers (3, 76), the high number of patients with mutations in other related tyrosine kinase genes (FGFR2, EGFR/ERBB1, and ERBB4) suggest that these should also be considered important genes in gastric cancer biology.