A 63-year-old man comes to the clinic for recent unintentional weight loss. The patient also has epigastric discomfort after meals. He has no known medical problems and takes no medications. His blood pressure is 130/75 and pulse rate is 88/min. He is not febrile. Upper endoscopy shows a lesion in the stomach that shows typical features of diffuse-type adenocarcinoma presenting with signet ring cells that do not form glands.