Gastric adenocarcinoma (GAC) is a global health burden on all societies, and it was the third-leading cause of cancer-related mortality in 2012, causing 723,000 deaths worldwide. The prognosis of patients with metastatic GAC remains poor, with a median overall survival of less than 1 year in patients treated with currently available therapies. A limited number of therapeutic agents is currently available. Recent additions to the armamentarium include trastuzumab and ramucirumab, which have shown some survival advantage when added to cytotoxic(s). Genomic analyses have defined various genotypes of GACs. The novel genomic knowledge can lead to discovery of novel targets and novel therapeutic agents. In this update, we focus on the current genomic data, targeted therapies including immune system modulators, and expand on HER2/neu testing and the use of agents against this target. Several other facets of GAC and its therapy are not to be included in this review but have been discussed elsewhere.