It is reported that Lactobacillus produces short-chain fatty acids (SCFAs), which reduce the expression and function of intestinal P-glycoprotein (P-gp) and upregulate breast cancer resistance protein (BCRP), leading to tumor suppression via the inhibition of HDAC/NF-κB and activation of PPARγ (Xie et al., 2021). The gene discussed is HDAC9; the disease is neoplasm.