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. Here, BAK1 is linked to hepatocellular carcinoma.