FMO3 and hepatocellular carcinoma: To further confirm that B. coccoides could produce TMA/TMAO, B. coccoides was co-cultured with Choline in vitro, and the resulting fermentation broth was used to treat HCC-LM3 cells, which express the FMO3 enzyme capable of converting TMA to TMAO (Figure 2J and S1D–K).