The aim of this study is to develop a protocol for detection of circulating tumor DNA (ctDNA) in plasma of patients with early stages of gastric cancer.

Gastric cancer (GC) is the fifth most common cancer worldwide and the third leading cause of cancer deaths. Earlier detection of GC can dramatically increases the five-year survival rate up to > 90%. The current endoscopy and tissue biopsy remain excessively expensive for middle-income nations, in addition to being fairly invasive, with possible complications. Additionally, most of serum-based biomarkers such as carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), carbohydrate antigen 72-4 (CA72-4), and carbohydrate antigen 125 (CA125) are not recommended for detection of GC due to the limit of specificity and sensitivity in the early stages of GC. Thus, it is essential to identify new biomarkers for diagnosis of early stages of GC. In this study, the investigators develop an ultradeep massive parallel sequencing (MPS) assay to detect tumor derived mutations (TDM) in plasma of early stages of GC. This study provides proof-of-principle for eventual clinical employment of circulating DNA, via liquid biopsy, for detection of early stages of GC.

Inclusion Criteria:

1. Male or Female patients aged 18 years and older
2. Histologically proven stage (I, II and IIIA) gastric adenocarcinoma
3. Naivety to treatment.
4. No known other concomitant cancer diagnosis
5. Signed informed consent

Exclusion Criteria:

1. Pathologically late stage (stage IIIB and IV) or metastatic gastric adenocarcinoma
2. Underwent any type of treatment
3. Unable to undergo biopsy

Patients diagnosed with early and locally advanced stage (I, II and IIIA) gastric cancer