PCNA and gastric cancer: For example, Zhang et al. obseved that GRg5 can increase the expression of P21 by reducing the production of the CCNG1/CDK 2/PCNA complex, causing cell cycle arrest in the S phase, and GRg5 can also regulate the cell cycle by inhibiting Notch1 protein expression, thus inhibiting the progression of AGS and MKN-45 in gastric cancer cells (Zhao et al., 2020); Liu et al. obseved that GRg5 can regulate the ROS-mediated MAPK pathway to induce gastric cancer cells SGC-7901 and BGC-823 to block the G2/M phase (Liu and Fan, 2019).