In gastric adenocarcinoma, downregulation of HMGB3 expression can dramatically suppress cancer cell proliferation, mainly through inducing G0/G1 blockade in tumor cells, regulating p53 and p21 signaling pathways, and reducing Bcl-2/Bax (anti-apoptotic factor/pro-apoptotic factor) levels. The gene discussed is BCL2; the disease is cancer.