ERBB2 and breast carcinoma: On the other hand, PA induced cell cycle delay and CCAAT-enhancer-binding protein homologous protein (CHOP) dependent apoptosis and was also involved in activation of the endoplasmic reticulum (ER) stress response network via X-box activating protein 1 (XBP1) and activating transcription factor 6 (ATF6) in HER2/neu-positive breast cancer cells [151].