In the context of this study, the induction of TGF-β1/Smad2 signaling mediated by NNMT expression was detected in HMrSV5 human peritoneal mesothelial cells activated by SNU-16 exosomes, indicating that GC-associated PM could be triggered by NNMT-containing exosomes, via TGF-β/smad2 signaling [93]. Here, SMAD2 is linked to gastric cancer.