TLR4 and neoplasm: Furthermore, an engineered Salmonella typhimurium secreting heterologous flagellin B (FlaB) was found to induce phenotypic and functional activation of M1-like macrophages via TLR4 instead of TLR5, which is the commonly known receptor for the FlaB ligand, which in turn suppressed tumor growth and inhibited metastasis [46].