ERN1 and cancer: In addition, PA-MSHA has been reported to induce endoplasmic reticulum (ER) stress in breast cancer cell lines through the IRE1 signaling pathway [33] indicating that combination of PA-MSHA and tyrosine kinase inhibitors may promote cancer cells apoptosis through up-regulation of the endoplasmic reticulum (ER) stress-induced apoptosis pathways.