The specificity was further confirmed by quantification of the differential gene expression between hepatoma and para-hepatoma liver tissues using RT real-time PCR in the 9 randomly selected genes, of which six (GBA, PTPRF, GNL3, ERBB3, OGDH, FMO3) were identified to be differentially expressed only by the SSH/microarray assays, but not the conventional cDNA microarrays assays. The gene discussed is PTPRF; the disease is hepatocellular carcinoma.