TLR4 and Carcinoma, Lewis Lung: Utilizing TLR4-deficient myotubes and TLR4 knockout mice, they demonstrated that Lewis lung carcinoma (LLC) cells release unidentified factors that directly activate TLR4 and its downstream p38 MAPK–C/EBPβ and NF-κB signaling pathways in skeletal muscle cells to induce muscle catabolism mediated by the UPP and ALP, which is in congruent with the established effects of LPS [52].