Discrimination of hepatitis C virus in liver tissues from different patients with hepatocellular carcinomas by direct nucleotide sequencing of amplified cDNA of the viral genome.

We investigated the presence of the hepatitis C virus (HCV) genome in liver tissues of eight different patients with hepatocellular carcinoma by using the reverse transcriptase polymerase chain reaction (PCR) method. RNA was extracted separately from cancerous and peripheral noncancerous portions of the liver tissues of each patient. For reverse transcriptase PCR, we used sets of primers derived either from nonstructural region 3 (the NS3 region) or from the nucleocapsid-envelope (C/E) region of the HCV genome. The nucleotide sequences of the amplimers were directly determined without subcloning. Of 16 samples tested, cDNA of the HCV genome was detected in 2 cancerous tissues and in 4 noncancerous tissues by either pair of primers. Nucleotide sequences of HCV cDNA fragments amplified from cancerous and peripheral noncancerous tissues from the same patients were identical. However, 4.4 to 6.3% and 7.5 to 11.3% sequence variation was observed in NS3 and C/E regions, respectively, among cDNA fragments from different patients. The result indicated that the HCV genome detected in a given patient is distinguishable from that in others by a simple direct nucleotide sequencing of the reverse transcriptase PCR products.