CD274 and neoplasm: The use of this methodology to characterise exosomes for HER2 receptor ratios, FOXC2 and other EMT markers, metalloproteases, TGFβ; and PD-L1, and other markers of therapeutic resistance can accompany the other developments in liquid biopsy, such as circulating tumour cells (CTCs) (53) and patterns of cell-free nucleic acids in plasma (54), as well as protein biomarkers in other biofluids such as tears (55), to predict disease development and progression.