TLR9 and hepatocellular carcinoma: PRRs are capable of promoting the cancer shaping, to be specific, TLR9 activation by mitochondrial DNA in a hypoxic environment can induce the growth of hepatocellular carcinoma cells (9); TLR2 takes charge of triggering MyD88-IRAK1 signaling in the epithelial cells of breast cancer for inducing cell proliferation (10); activation of TLR2, TLR4, TLR7, TLR9 and NLRP3 can trigger multiple pro-tumor activities in pancreatic cancer (11).