In addition, miR-155 has been shown to promote breast cancer resistance by inhibiting its direct target gene, tetraspanin-5 (TSPAN5) [22], and by enhancing the activity of several major signaling pathways, including mitogen-activated protein kinase (MAPK), RHOA, and transforming growth factor beta (TGF-β) [21]. Here, TSPAN5 is linked to breast cancer.