TLR9 and neoplasm: Tumor cells can release HMGB1 into the local microenvironment, where HMGB1 binds with high affinity to several receptors, such as toll like receptor-2 (TLR-2), TLR-4, TLR-9 and advanced glycation end products (RAGE), which can lead to tumor cell survival, expansion and metastasis [27].