Using doxorubicin accumulation assay as reporter of MRP1 activity, our results indicate that GQDs nanoparticles did not interfere with the MRP1 efflux activity of doxorubicin suggesting it did not compete with doxorubicin and that GQDs nanoparticles would be very suitable for doxorubicin delivery to cancer cells and to bypass the efflux activity of MRP1. This evidence concerns the gene ABCC1 and cancer.