Poor prognosis of hepatocellular carcinoma (HCC) is due to its high recurrent rate after operation and early metastasis through portal vein. This study was designed to establish a metastatic HCC cell line and to investigate its molecular and cytogenetic characterization.,Cell culture was performed using the tissue obtained from a metastatic lesion in portal vein of a patient with HCC. After G-banding staining, karyotype, and comparative genomic hybridization (CGH) of the cultured H4M cells were characterized and cyclin D1 gene CCND1 was detected by differential PCR.,The karyotype of metastatic HCC cell strain is a hypertriploid (71-78 chromosomes) with a huge marker chromosome containing a long homogeneously staining region (hsr). The main genetic alterations in H4M cells were a high copy number amplification of 11q13 and loss of 8p. Cyclin D1 gene CCND1 was also amplified significantly in the cells.,The loss of chromosome 8p and high copy number amplification of 11q13 are associated with the metastatic characteristics of H4M cells. The amplification of cyclin D1 gene CCND1 in H4M cells may be the cause of the amplification of chromosome 11q13.