Through inhibiting histone deacetylases (HDACs), butyrate could inactivate several oncogenic signaling pathways in cancerous cells (Wan et al., 2017), e.g., mitogen-activated protein kinase 1 (MAPK1) signaling pathway which inhibits apoptosis and promote rapid proliferation of cancer cells (Li et al., 2017), and small mothers against decapentaplegic homolog 3 (SMAD3) signaling pathway, one of the key activators in the process of epithelial-mesenchymal transition (Wawruszak et al., 2019). The gene discussed is MAPK1; the disease is cancer.