NCI: An adenocarcinoma that arises from and straddles the junction of the stomach and esophagus. The category of adenocarcinomas of the gastroesophageal junction also includes the majority of adenocarcinomas previously called gastric cardia adenocarcinomas. Squamous cell carcinomas that affect or cross the junction of the stomach and esophagus are classified as carcinomas of the distal esophagus. Adenocarcinoma of the gastroesophageal junction occurs more often in Caucasian middle aged and elderly males. Clinical signs and symptoms include dysphagia, abdominal pain, and weight loss. The prognosis depends on the completeness of the surgical resection, the number of lymph nodes involved by cancer, and the presence or absence of postoperative complications. The presence of TP53 mutations indicates worse prognosis.