Genetic variants in the AGO2 gene lead to the loss of AGO2 expression, including frameshift mutations in the AGO2 gene with high microsatellite instability (MSI-H) in gastric cancer and CRC27, single nucleotide polymorphisms of AGO2 in breast cancer28, and AGO2 mutations in glioma29. The gene discussed is AGO2; the disease is gastric cancer.