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. This evidence concerns the gene FOXC2 and neoplasm.