CHROMOSOMAL-ABERRATIONS IN HEPATOCELLULAR CARCINOMAS - RELATIONSHIP WITH PATHOLOGICAL FEATURES

Fluorescence in situ hybridization performed on tissue sections can re veal chromosomal abnormalities related to histopathological features. This technique was performed on serial frozen sections from seven norm al livers and 29 hepatocellular carcinomas (HCCs) using pericentromeri c repeat-specific probes for chromosomes 1, 4, 6, 7, 8, 16, and 17. Fo r each HCC and each probe, the percentage of cells showing one, two, o r more than two signals was counted and compared with the distribution in the normal liver. According to these results, HCCs were categorize d as monosomic, disomic, or polysomic (more than two signals) for the chromosome tested. These data were compared with the main histopatholo gical characteristics of HCC, Chromosome gains were very common, prefe rentially affecting chromosome 1 (23 of 27 cases, 85%), chromosome 16 (16 of 27 cases, 59%), chromosome 7 (16 of 29 cases, 55%), chromosome 6 (15 of 29 cases, 52%) and chromosome 8 (14 of 29 cases, 48%). Monoso my was seen more rarely, affecting preferentially chromosome 16 (19%), chromosome 17 (14%), and chromosome 4 (10%), A significant correlatio n was observed between aneusomy of chromosome 4 and tumor size (P < .0 5) or the presence of vascular embolism (P < .05). In conclusion, chro mosomal gains are frequent genetic events in human HCC, A significant association between a gain in chromosome 4 and large tumor size or vas cular embolism suggests that this genetic abnormality is a late event in liver carcinogenesis.