PGP and breast carcinoma: The intracellular uptake of nanocarriers determined using fluorophore tagged fluorescence microscopy imaging in P-glycoprotein (P-gp) over-expressing MCF-7/Adr breast carcinoma cells was 12.4-fold higher than that of free VCR revealing that P-gp mediated efflux of VCR was considerably reduced by the graft polymer–based NPs [61].