Ji et al. reported that mesenchymal stem cells (MSCs) derived exosomes could induce the resistance of GC cells to 5-fluorouracil (5-FU), which may be associated with its role in activating Ca2+/Raf/MEK/ERK signaling pathway and upregulating the expression of multidrug resistant proteins in GC cells [39]. The gene discussed is MAP2K7; the disease is gastric cancer.