Treatment with stigmasterol, an active phytosterol compound found in plant oils and seeds, was shown to reduce tumor size in mice and increase the abundance of Lactobacillus johnsonii, Lactobacillus murinus, and Lactobacillus reuteri, enhancing the immune response in the HCC tumor microenvironment by increasing the number of interferon-gamma (IFN-γ)+ CD8+ T cells and Treg cells [45]. The gene discussed is CD8A; the disease is hepatocellular carcinoma.