Our observation that both growth factor‐evoked and spontaneous Ca2+ transients in PyMT breast tumour cells do require SK4 activity is consistent with the TRAM‐34 sensitivity of the cell cycle and abundance of c‐fos and c‐jun (Lai et al., 2011; Ouadid‐Ahidouch et al., 2004; Wang et al., 2007b). This evidence concerns the gene FOS and breast neoplasm.