Another explanation for CAF-mediated Trastuzumab resistance resides in the newly identified subset of BC CAFs that express CD16 (also known as FcγRII, a cluster of differentiation molecule found on the surface of natural killer cells, neutrophils, monocytes, macrophages, and certain T cells) and which abundance in HER2-positive patients is associated with poor prognosis and resistance to Trastuzumab. Here, ERBB2 is linked to breast cancer.