AFP and liver cancer: The existing findings support that increased richness of Veillonella is closely related to the progression of various liver diseases, including autoimmune hepatitis, primary biliary cirrhosis, and alcoholic hepatitis (Lv et al., 2016; Cortez et al., 2020; Lang et al., 2020; Kim et al., 2021; Wei et al., 2020), and it is also positively correlated with the level of alpha fetoprotein (AFP) in patients with primary liver cancer (Zhang et al., 2019).