COL4A1 and hepatocellular carcinoma: Furthermore, COL4A1 was the most significantly upregulated collagen gene in HCC in term of average fold changes (cancerous tissues/noncancerous liver tissues, 1.69 for COL1A1; 1.69 for COL1A2; 2.10 for COL4A1 and 1.92 for COL4A2).