On the one hand, HBx survivin-dependently down-regulates tumor suppressor miR-520b through modulating transcription factor Sp1 and then miR-520b inhibits the expression of oncoprotein HBXIP through targeting its 3'UTR; on the other hand, HBx induces demethylation of HBXIP promoter with partner survivin, resulting in up-regulation of HBXIP. The gene discussed is SP1; the disease is neoplasm.