A recent study by Gueder and coworkers revealed that treatment of the breast cancer MCF7 and MDA-MB-231 cell lines with the pseudo-C-octyl glycoside 2-oxa-3-oxocastanospermine derivatives (CO-OCS), inhibitors of α-glycosidase, significantly decreased the expression of STIM1 at the protein level and attenuated SOCE. This evidence concerns the gene STIM1 and breast carcinoma.