COL4A1 and hepatocellular carcinoma: To investigate the different role of each isoform of COL IV in hepatocarcinogenesis, the HCC expression profile was analyzed using public sequencing data in GEO and TCGA, in which among the six COL IV isoforms, only COL4A1 and COL4A2 was significantly upregulated from preneoplastic lesions (cirrhosis and dysplasia) to HCC.