A recent example is represented by the synthesis of hyaluronic acid-derivatized PLGA nanoparticles to actively target the CD44 receptors present on the surface of breast cancer cells and selectively delivering the antitumoral molecule tamoxifen, well known to be active against estrogen receptor-positive breast cancer cells, thus reducing the correlated side-effects [26]. This evidence concerns the gene ESR1 and breast carcinoma.