Exosomes and exosomal RNAs in breast cancer: A status update

Improved treatment of breast cancer, the world's second most common cancer, requires identification of new sensitive prognostic and diagnostic biomarkers. Exosomes are lipid-bilayer extracellular vesicles of size 30-150 nm, released by all cell types, including breast cancer cells. Cellular communication is the primary function attributed to them. This review discusses the potential utility of exosomes and exosomal RNAs (microRNAs [miRNAs]/long non-coding RNAs [LncRNAs]) in breast cancer biology and treatment. The existing literature shows that exosomes play a significant role in breast tumorigenesis and progression through transfer miRNAs and LncRNAs. These miRNAs and LncRNAs function by post-transcriptionally regulating their target mRNAs, eventually leading to modulation of expression/repression. Over the past two decades, numerous publications point towards diagnostic and therapeutic applications of exosomal miRNAs/LncRNAs. Until now, we do not have clinically approved exosome-based therapeutics. Therefore, it is high time that clinicians and cancer researchers utilise exosome's benefits through randomised clinical trials for better management of breast cancer.