MMP2 and hepatocellular carcinoma: The further analysis showed that a total of 121 genes were included in the 13 OAMs; according to the expression levels of the 121 genes in the microarray data, a total of 7 differentially expressed genes were identified between any two groups, including cyp2b6 (CHB vs. HCC groups), pi3 (cirrhosis vs. HCC groups), and mmp2, pi3, ptk2, timp2, tnfrsf10b (CHB vs. cirrhosis groups).