TLR4 and neoplasm: Our previous studies reported that two cationic polymers, namely cationic dextran (C-dextran) and polyethyleneimine (PEI), stimulated macrophages to produce immune-activating cytokine IL-12 via toll-like receptor 4 (TLR4) signalling27, and re-directed tumour-associated macrophages (TAM) from a immunosuppressive to tumour-killing phenotype29.