Loss of somatic heterozygosity in hepatocellular carcinoma

Abstract

Loss of tumor suppressor genes is involved in the mechanism of tumorigenesis of many solid tumors. We tested 9 hepatitis B virus (HBV)-positive and 10 HBV-negative hepatocellular carcinomas for loss of somatic heterozygosity using 14 polymorphic probes mapping to chromosomes 4, 11, 13, and 17. Losses were found on all chromosome arms tested. The highest frequency of loss was observed at the D13S1 locus (67%) at band 13q12. Losses were also observed at three other loci on 13q. Twenty-one % of informative cases showed loss on 17p using the probe pYNZ22 which maps near the p53 locus. Losses on 4q were infrequent with 17% found at one locus and no loss at two others. The retinoblastoma gene and the locus on 17p were only inactivated in our HBV-negative tumors, although the numbers were too small for statistical significance. For all loci tested, we found no significant differences in the frequency of losses with HBV status, ethnic background, cirrhosis, grade of tumor, or presence of hemochromatosis.