Toll-like receptors: New targets for multiple myeloma treatment?

Despite recent biomedical improvements in treating multiple myeloma, this disease still remains incurable. Toll-like receptors (TLRs) are key immune receptors that recognize conserved molecular patterns expressed by pathogens and damaged cells. Activation of TLRs can induce several effects including inflammatory responses, modulation of cell cycle, apoptosis, or regulation of cell metabolism. In multiple myeloma there is a dysregulated signalling of TLRs due to an abnormal presence of certain pathogens and release of molecules from damaged cells. Thus, TLRs could be critical players for tumour microenvironment and multiple myeloma progression. This haematological malignancy is characterized by a high percentage of recurrences, where many patients can develop residual drug-resistant malignant cells. Strategic targeting of TLRs might result in novel therapeutic combinations that improve the response to current treatments, reducing relapses. This review examines the potential of TLRs as targets for the treatment of multiple myeloma, making a particular emphasis on their therapeutic applications.