Previous studies have shown that MMP9 expression can be downregulated by reducing AKT/mTOR levels that promote H3K27Ac and H3K56A on the MMP9 promoter region, thereby inhibiting the proliferation and metastasis of triple-negative breast cancer [32], and that MMP-9 can also promote the invasion and migration of gastric cancer cells through the ERK pathway [33]. The gene discussed is MMP9; the disease is gastric cancer.