ARHI, also known as DIRAS3, belongs to the small GTPase superfamily, Di-Ras family. ARHI gene is a novel tumor suppressor gene located on chromosome 1p31. Downregulation of ARHI expression has been detected in many types of cancer. ARHI is expressed in normal ovarian and breast epithelial cells but not in ovarian and breast cancers. As a suppressor, ARHI is not only an important factor in the pathogenesis of gastric cancer, but also a potential factor for tumor aggravation. ARHI expression in gastric cancer can be employed to indicate favorable prognosis for the disease.