Future of PD-1/PD-L1 axis modulation for the treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC) has the worst prognosis among the subtypes of breast cancer, with no targeted therapy available. Immunotherapy targeting programmed cell death protein-1 (PD-1) and its ligand (PD-L1) has resulted in some promising outcomes in cancer patients. The common treatments are monoclonal antibodies (mAbs). Despite novel methodologies in developing mAbs, there are several drawbacks with these medications. Immunological reactions, expensive and time-consuming production and requiring refrigeration are some of the challenging characteristics of mAbs that are addressed with using aptamers. Aptamers are nucleotide-based structures with high selectivity and specificity for target. Their small size helps aptamers penetrate the tissue better. In this review, we have discussed the nature of PD-1/PD-L1 interaction and summarised the available mAbs and aptamers specific for these two targets. This review highlights the role of aptamers as a future pathway for PD-1/PD-L1 modulation.