PDZK1 and breast cancer: NHERF‐1, NHERF‐2, and PDZK1 are abundantly expressed in breast cancer or cell lines (Ghosh et al. 2000; Stemmer‐Rachamimov et al. 2001), where NBCn1 is responsible for pH regulation (Lauritzen et al. 2010; Boedtkjer et al. 2012).