ID1 and hepatocellular carcinoma: We detected the mRNA expression levels of Id-1 and CCN2 in 48 HCCs and their adjacent non-tumor liver tissues, and found increased Id-1 expression in 70.83% (34/48), and increased CCN2 expression in 64.58 (31/48) of HCC tissues compared with the corresponding non-tumor liver tissues (Fig. 2a, b).