Impact of pattern recognition receptors on the prognosis of breast cancer patients undergoing adjuvant chemotherapy

Pattern recognition receptors allow the innate immune system to perceive the presence of microbial products and to launch the first steps of the defense response. Some pattern recognition receptors also sense endogenous ligands that are released from uninfected dying cells, thereby activating immune responses against dead-cell antigens. This applies to toll-like receptors 3 and 4 (TLR3, TLR4), which sense double-stranded RNA and high-mobility group protein B1 (HMGB1), respectively, as well as to formyl peptide receptor-1 (FPR1), which interacts with Annexin A1 (ANXA1) from dead cells. Breast cancer patients who bear loss-of-function alleles in TLR3, TLR4, and FPR1 exhibit a reduced metastasis-free and overall survival after treatment with anthracycline-based adjuvant chemotherapy. These genetic defects are epistatic with respect to each other, suggesting that they act on the same pathway, linking chemotherapy to a therapeutically relevant anticancer immune response. Loss-of-function alleles in TLR4 and FPR1 also affect the prognosis of colorectal cancer patients treated with oxaliplatin-based chemotherapy. Altogether, these results support the idea that conventional anticancer treatments rely on stimulation of anticancer immune responses to become fully efficient.