ERBB2 and cancer: This positions GC as the fifth most prevalent cancer worldwide and the fourth leading contributor to cancer‐related mortalities.[3, 4] The recombinant antibody for HER2 represents the sole targeted pharmaceutical intervention that has demonstrated efficacy in the treatment of patients with advanced GC.[5, 6] The oncogene HER2, also referred to as ERBB2, undergoes amplification and the corresponding protein HER2 is high‐expressed in ≈17–20% of patients diagnosed with GCs.