S. typhimurium L forms can penetrate deep into the interior of tumors and perform their growth and proliferation, thereby inhibiting the growth of ovarian cancer, plundering the nutrients inside the tumor, producing toxic metabolic waste, inducing cancer cell death, leading to restricted growth of ovarian cancer, delayed cell proliferation and tomur volume growth, and reduced expression of Lgals9, MMP9, and E-cadherin proteins in ovarian cancer cells. The gene discussed is CDH1; the disease is ovarian cancer.