Many studies have shown that potassium channels, including KCNN4 (Steudel et al., 2017), KCNA1 (Lallet-Daher et al., 2013), Kv11.1 (Breuer et al., 2019), KCNK9 (Mu et al., 2003; Sun et al., 2016), KCNE1 (Becchetti et al., 2017), and GIRK1 (Stringer et al., 2001) are involved in the regulation of malignant breast cancer transformation. Here, KCNK9 is linked to breast cancer.