In ERBB2‐targeted therapy: HER2 Δ16 evades trastuzumab binding and constitutively activates signaling [294]; the ERBB2 i14e isoform causes trastuzumab resistance in gallbladder cancer, which is reversible by ASOs [57]; an ERBB2 deletion (c.644‐66_‐2del) leads to loss of the pertuzumab‐binding domain in metastatic CRC [295]. Here, ERBB2 is linked to gallbladder cancer.