Fu et al. [10] found that intracellular bacteria could promote lung metastasis of breast cancer cells, the mechanism of which may be that intracellular bacteria invade tumor cells, remodel the cytoskeleton via the RhoA–ROCK pathway, enhance the tolerance of circulating tumor cells to intravascular mechanical pressure, and reduce cell death during metastasis. The gene discussed is RHOA; the disease is breast carcinoma.