Inclusion Criteria:  patients diagnosed with primary gastric adenocarcinoma; no neoadjuvant therapy; age: 18 to 90 years old; gender: men or women; signed informed consent for EUS with contrast-enhancement and tissue sampling;  Exclusion Criteria:  other types of gastric cancer than adenocarcinoma; prior treatment with chemo-radiotherapy; failure to provide informed consent; severe coagulopathy.