When exposed to hypoxia and radiation, histone H3 methylation of gastric adenocarcinoma cells was in a state of dynamic transformation, and JMJD2B-mediated modification mechanisms function to enhance the expression of cyclin A1 (CCNA1) and further facilitate the growth of gastric adenocarcinoma cells under hypoxia and radiation stress (67). The gene discussed is CCNA1; the disease is gastric adenocarcinoma.