MAPK9 and gastric cancer: Previous studies reported several molecular mechanisms involved in PA-induced autophagy in different cell models, such as the Ca2+ leakage of the endoplasmic reticulum (ER) in endothelial cells16, the activation of transcription factor p8-p53-PKC α signaling in human gastric cancer MKN45 cells18, the modulation of protein kinase C in MEFs cells35, the promotion of JNK2 signaling pathway in hepatocytes36 and the dysfunction of mitochondria and excess of reactive oxygen species (ROS) in podocytes37 and hepatocytes38.