PRG4 and hepatocellular carcinoma: Through microarray gene expression analysis (data set: www.ncbi.nlm.nih.gov/geo; accession number: GSE54236), in a prospective study involving a cohort of 78 HCC patients we determined the mRNA expression levels of different PGs, including chondroitin sulfate proteoglycan 4 (CSPG4), perlecan (HSPG2), VCAN, and PRG4 in tumor and paired peritumor tissues.