CD44 and breast cancer: Furthermore, CD44 has been demonstrated to play a role in the development of drug resistance in breast cancer cells treated with Trastuzumab, Lapatinib, and Tamoxifen (Hiscox et al., 2012; Lesniak et al., 2013; Boulbes et al., 2015), therefore targeting CD44 in conjunction with other potential drug targets remains of high interest.