Use of Circulating Exosomal LncRNA-GC1 to Monitor Gastric Cancer

Background: Although its incidence and mortality has decreased, gastric cancer (GC) is the fourth most common cancer and the second leading cause of cancer-related death worldwide, particularly in China. The number of new cases and deaths may comprise approximately one-half of the global total. The high mortality of GC is partially attributed to late detection and nonspecific symptoms. The current gold standard for diagnosing GC is endoscopic biopsy. However, because of its discomfort to the patient and high cost, screening for early GC (EGC) is a major difficulty in clinical practice, particularly for asymptomatic individuals. Unfortunately, gastric precursor lesions such as intestinal metaplasia (IM), chronic atrophic gastritis (CAG), and persistent Helicobacter pylori (HP) infection increase the difficulty of screening for EGC. Furthermore, the standard serum biomarkers for GC, such as CEA, CA72-4, and CA19-9 achieve a low positive rate. Thus, it is critically important to develop new approaches for diagnosing EGC with high specificity and sensitivity. Objective: To study circulating exosomal lncRNA-GC1 as a potential biomarker for detection of gastric cancer. Eligibility: Participants from two medical centers in China Design: Investigators will use blood samples from participants in the two medical centers. Investigators will use samples from some who developed gastric cancer. The other samples will be from some who stayed cancer free in that time. Participants already gave written informed consent. Investigators will take exosomes from the samples and look for lncRNA-GC1.