INTERPHASE CYTOGENETIC STUDIES OF HUMAN HEPATOCELLULAR CARCINOMAS BY FLUORESCENT IN-SITU HYBRIDIZATION

Although numerous allelic chromosome losses have been reported in hepa tocellular carcinomas (HCC), chromosome analysis by cytogenetic method s has rarely been performed in these tumors, unlike in other solid mal ignant tumors, The purpose of the current study was to analyze primary liver tumors by conventional cytogenetic methods and by a new molecul ar cytogenetic technique, called fluorescent in situ hybridization (FI SH), a technique that has been recently proposed to count the number o f chromosome copies in interphase nuclei with chromosome centromeric p robes, Primary cultures of tumoral cells were prepared to obtain metap hases, Specific chromosomes probes 7, 17, and 20 were used to perform in situ hybridization on isolated intact tumoral cells. Seven cases of primary liver tumors (six cases of HCC and one case of benign focal h epatic nodular hyperplasia) were investigated, A few metaphases were o btained in five of the seven tumors, and in most cases numerical abnor malities were difficult to interpret. In contrast with in situ hybridi zation, all cases of HCC showed losses and/or gains of chromosomes, Lo ss of one to three chromosomes occurred in five tumors. A gain of two chromosomes was observed in two of these five tumors, In only one case , a gain of only three chromosomes occurred, In addition, a loss of ch romosome 17 was recorded for the benign tumor, These results demonstra te that FISH with specific probes can provide information on chromosom e number in the tumoral cells of primary liver tumors even in the abse nce of analyzable metaphases, This technique opens new possibilities f or the investigation of chromosome abnormalities in HCC.