Supporting this notion, the nanoparticles of anti- CD44 Ab encapsulating anti-IL-6R Ab target the TME and CD44+ BCSCs that inhibit the metastatic niche of triple-negative and luminal breast cancer in two mouse models, namely syngeneic BALB/c mice bearing 4 T1 cells and transgenic MMTV-PyMT mice [12]. Here, IL6R is linked to breast cancer.