When exosomes were absorbed by HCC cells, circ-0051443 bound to miR-331-3p competitively and reduced the expression of Bcl2 Antagonist/Killer 1 (BAK1) which is an important cell death regulator, thereby promoting apoptosis of HCC cells and inhibiting cell cycle to control the progression of malignant tumors. The gene discussed is BCL2; the disease is hepatocellular carcinoma.