Inclusion Criteria:  Male or Female patients aged 18 years and older Histologically proven stage (I, II and IIIA) gastric adenocarcinoma Naivety to treatment. No known other concomitant cancer diagnosis Signed informed consent  Exclusion Criteria:  Pathologically late stage (stage IIIB and IV) or metastatic gastric adenocarcinoma Underwent any type of treatment Unable to undergo biopsy