Table 1.
Roles of TLRs in lung cancer.
| TLR Pathway | Main Cell Types Involved | Pro-tumorigenic Activity | References |
|---|---|---|---|
| TLR2 | Lewis lung carcinoma MDSCs |
TLR2/6 promote tumor growth and metastasis | (22) |
| M1 macrophages | TLR1/2 promote M1 macrophages | (23) | |
| TLR3 | Tumoral exosomes Lung epithelial |
Sensing tumoral RNA to promote metastasis | (24, 25) |
| TLR4 | Human lung cancer | Upregulated in lung carcinomas, induces immunosuppressive cytokines and resistance to apoptosis | (26) |
| NSCLC | Upregulates PD-L1 expression | (27) | |
| TLR7 | NSCLC | Promotes tumor progression and chemotherapy resistance | (28) |
| TLR8 | Primary lung tumors | Upregulated in lung carcinoma | (29) |
| TLR9 | Human lung tissue | Upregulated in lung carcinoma | (30) |
| Promotes metastasis and progression | (31) | ||
| TLR Pathway | Main Cell Types Involved | Anti-tumorigenic Activity | References |
| TLR2 | Mast cells | TLR2 activation on mast cells reversed pro-tumor role | (32) |
| TLR3 | NSCLC | Induces apoptosis Reactivate local innate responses |
(33) |
| TLR4 | NSCLC DCs |
Inhibits NSCLC by regulation | (34, 35) |
| TLR5 | NSCLC | Upregulates anti-tumor effect | (36) |
| TLR7/8 | DC and NK | Enhances DC and NK cell activation | (37, 38) |
| TLR7 | NSCLC | Inhibits angiogenesis | (39) |
| TLR9 | PBMCs Human primary |
TLR9 activation by CpG-ODN induces an anti-tumor activity | (40) |