We observed a dramatic redistribution of inositol trisphosphate receptors (IP3Rs) and stromal interaction molecule 1 (STIM1)-competent endoplasmic reticulum–plasma membrane junctions (ER–PM junctions) when pancreatic ductal adenocarcinoma (PDAC) cells disconnect from their neighbours and undergo individual migration. This evidence concerns the gene STIM1 and pancreatic ductal adenocarcinoma.