LOSS OF HETEROZYGOSITY IN CHROMOSOME 4Q12-Q13 IN HEPATOCELLULAR-CARCINOMA IN SOUTHERN AFRICAN BLACKS

Paired samples of hepatocellular carcinoma and non-tumorous hepatic ti ssue from 12 southern African blacks were examined for loss of heteroz ygosity at two loci (D4S409 and D4S392) in chromosome 4q12-q13 (mappin g to the same region as the locus for the gene for alpha-fetoprotein). Deoxyribonucleic acid was extracted from carcinoma and non-tumorous t issues and amplified using the polymerase chain reaction. The primers used were based on flanking regions of minisatellite DNA specific for the loci. Products of PCR amplification were separated by denaturing p olyacrylamide gel electrophoresis and analysed for allelic losses. At the D4S409 locus one of seven informative samples showed loss of heter ozygosity, whereas none of eight informative samples showed loss of he terozygosity at the D4S392 locus. If these findings are considered tog ether with those previously reported in hepatocellular carcinomas from black Africans, the prevalence of loss of heterozygosity in chromosom e 4q12-q13 in hepatocellular carcinoma in southern African blacks (33 per cent) is the same as that in tumours from Japanese patients. Loss of heterozygosity at chromosome 4q12-q13 is infrequent during hepatoce llular carcinogenesis in southern African blacks.