GDF2 and hepatocellular carcinoma: Furthermore, CEUS showed that the perfusion images and intra‐tumoural signal intensity of the maximum section of tumours were higher in xenografts derived from BMP9‐overexpressing HBV‐infected HCC cells than in those derived from HBV‐infected HCC cells or HBV‐uninfected HCC cells (Figure 4G, Supporting Information Figure S3B,C).