In the present study, we found that expression of CBFβ and NFκB was significantly increased in gastric cancer tissues while knockdown of CBFβ or NFκB dramatically inhibited the expression of APOBEC family and AICDA genes, diminished deaminase activity, and reduced the frequency of NKX6.3 depletion-induced mutations in TP53, PIK3CA, and POLA1 genes. The gene discussed is AICDA; the disease is gastric cancer.