Table 1.

Impact of compounds that affect toll-like receptor TLR2 and TLR4 activity or expression in breast cancer

Ligand	Ligand type	Biological function	Impact on breast cancer	References
HMGB1	Endogenous DAMPs	Critical regulator of cell death and survival	Upregulated in most types of tumors; greater expression in tumors than normal epithelium	Tang et al83; Lotze and DeMarco;84 Lotze and Tracey;85
PGN	Exogenous PAMPs	Forms cell wall of bacteria	Promoted breast cancer cell invasiveness and adhesiveness in MDA-MB-231 breast cancer cells	Xie et al86
Serum amyloid A	Endogenous DAMPs	Potent chemoattractant	Elevated in breast cancer patients depending on stage	Hiratsuka et al87; Zhang et al88
Flagellin	Endogenous PAMPs	Forms flagella in bacterial flagellum	Suppresses cell proliferation and growth in breast cancer cells	Sfondrini et al89; Cai et al 201190

Abbreviations: DAMPs, damage-associated molecular pattern molecules; HMGB1, high-mobility group protein B1; PAMPs, pathogen-associated molecular patterns; PGN, peptidoglycan.