The aim of this study is to track tumor evolution of regional and distant metastases in gastric cancer using the Next Generation Sequencing technologies.

Gastric cancer is the fourth most common cancer in Vietnam with high mortality rate. Metastasis is the leading cause of death in gastric cancer patients, with median overall survival of less than 1 year. Currently, there is no effective treatment because the molecular mechanism of metastasis remains unclear. The aim of this study is to use advanced NGS technologies to dissect the genomic changes (genetic, epigenetic and transcriptional changes) of the primary tumor and associated metastatic sites of the same patients. With that, the investigators can reconstruct the clonal evolution from primary tumor to metastasis, identify key pathways governing metastasis development that can be targeted for future therapeutic development.

Inclusion Criteria:

1. Male or Female patients aged 18 years and older
2. Histologically proven primary gastric adenocarcinoma and clinical evidence of metastasis (N1-3M1)
3. Biopsies can be taken at multiple sites
4. No known other concomitant cancer diagnosis
5. Signed informed consent

Exclusion Criteria:

1. Gastric adnocarcinoma cannot be confirmed primary
2. Unable to undergo biopsy or surgery

Patients with metastatic gastric adenocarcinoma