GNAI1 and breast cancer: Previous studies of CaSR in cancer cell-lines, including MCF-7 human breast cancer cells and mouse pituitary AtT20 cells, have shown that CaSR switches from preferentially coupling to Gq/11 and Gi/o pathways to exclusively signalling by a Gs pathway (Mamillapalli et al. 2008, Mamillapalli & Wysolmerski 2010).