CD44 and breast cancer: The 2′F-Py modified RNA aptamer, named Apt1, which was selected against the human recombinant full-length CD44 protein, was proved to bind with high affinity to CD44-positive MDA-MB-231, MCF-7 and T47D breast cancer cells [99] and, when conjugated on the outer shell of liposomes, it efficiently drove their specific uptake into TNBC cells [100].