There are multiple types of GC based on a molecular basis, such as (i) positive GC for Epstein–Barr virus (EBV)(8% of the cases), which is because interferon-gamma (INFg) is produced as a response to chronic viral infection, which also has an anti-cancer function; (ii) 22% of GC cases present microsatellite instability (MSI), exhibiting a high amount of genomic alterations and multiple cancer-associated antigens; and (iii) gastric tumors that present chromosomal instability found in most of the GC cases (50%) [79]. This evidence concerns the gene IFNG and gastric cancer.