TABLE 1.

Anti‐tumor activity of the bacteria as carriers

Bacteria	Tumor model	Anti‐cancer mechanism	Ref:
Salmonella typhimurium (SL7207)	Melanoma (B16‐F10)	As a vaccine carrier, it activates the CD4+ and CD8+ T‐cell responses increase the production of specific Th1 cytokines, increases the tetramer cells, and inhibits lung metastasis	( 100 )
Salmonella typhimurium (VNP20009)	Murine T‐ALL cell line L1210	Increase the levels of TNF‐α, IFN‐γ, and CXCL‐10, and upregulate NKs, CD4+ Th1 type cells, and CD8+ T cells that produce IFN‐γ	( 101 )
Salmonella typhimurium (A1‐R)	Lung cancer (Lewis), Melanoma (B16), Pancreatic cancer	Destroy the tumor blood vessels. Promotes the CD8 + T‐cell infiltration and inhibits tumor growth and metastasis	( 102, 103 )
Listeria monocytogenes (Lmat‐LLO and Lm[ct])	A genetically engineered mouse model (GEMM) of melanoma	Increasing the level of intracellular Ca2 + , produces high levels of ROS, enhances specific CTL responses, and decreases tumor growth	( 104 )
Listeria monocytogenes (Lm ‐LLO‐Flk‐1)	Breast cancer (NT‐2 and J774A.1 cells)	A fetal liver kinase 1 (Flk‐1), as fusion proteins with the microbial adjuvant, LLO. Targeting the endothelial cells by Flk‐1 can induce the epitopes to spread to the endogenous tumor proteins, reduce the tumor micro‐vessel density, and cause tumor death	( 105 )
Bifidobacterium (displaying WT1 protein)	Leukemia (C1498‐WT1)	Significantly induce the tumor cells to infiltrate the CD4+ T cells and CD8+ T cells, producing systemic WT1‐specific cytokines, and cytotoxic activity mediated by the WT1 epitope‐specific cytotoxic T‐lymphocytes, and significantly inhibiting the WT1 gene expression for tumor growth in mice	( 106 )
E. coli Nissle 1917	colorectal cancer (CT26)B‐cell lymphoma (A20)	Checkpoint inhibitors delivered with probiotics can activate T cells, produce a remote effect, and increase the memory population of T cells throughout the body	( 86 )