 The purpose of this single arm study is to assess the safety and efficacy of ATAN Apatinib in patients with Chemo-refractory Advanced or Metastatic Adenocarcinoma of Stomach or Gastroesophageal Junction in clinical practice. ATAN will be given to patients who had failed at least two lines of prior chemotherapy. Eligible patients will receive ATAN treatment 850 mg qd p.o. continually until disease progression or intolerable toxicity or patients withdrawal of consent, and the target sample size is 2000 individuals. 