These findings imply the importance of the heterotrimeric G‐proteins in transducing the non‐genomic and genomic (transcriptional) signaling in response to the clinical relevant dose of (1 μm) 4‐OHT.58 In breast cancer cells, the Tam is known to act as agonist on GPCR 30 (GPR30)59, 60 and GPCR30/G‐protein coupled oestrogen receptor‐1(GPR30/GPER‐1).59, 60 GPCRs are cell surface receptors with wide spectrum of functions in physiological and pathophysiological processes that range from tumor formation to the spread of cancer cells. This evidence concerns the gene STIM1 and breast cancer.