TLR7 and cancer: The secreted microRNA serves as a key regulator of tumor microenvironment and implicates its function in tumor-immune system communication, and thus represents a potential target for cancer treatment.[39,40] Ochi agreed with these results, and believed that TLR7 signaling promoted carcinogenesis in mice and humans, and blockade of TLR7 protected host cells against tumor inflaming metastasis.[41] These opposite outcomes in cancer development indicate the host specificity of TLR signaling controls the fate of cancer.