TLR4 and breast cancer: Thus, to validate functionality of endotoxin-TLR4 signaling axis under ME conditions, we incubated human (MDA-MB-231) and murine (E0771) BC cells (expressing TLR4 receptor at levels comparable to those detected in human/murine cells of monocytic origin (Figure S1B)), with endotoxin (LPS, 0.1 ng/mL), reflecting levels typically observed in obese patients and in experimental ME [8,11,12,13,14,15,18].