MAPK1 and cancer: Of note, downregulation of CAF-derived secreted protein acidic and rich in cysteine (SPARC) can lead to dedifferentiation of gastric cancer cells to CD44+/CD24− cancer stem cell (CSC)-like cells, and the AKT/mTOR and MEK/ERK signaling pathways might be involved in these processes,148 indicating that CAF-derived SPARC maintained tumor stemness through the AKT/mTOR signaling pathway.