Metastasis is a major cause of cancer morbidity and mortality in individuals with hepatocellular carcinoma (HCC), yet little is known about the underlying molecular basis. Using genetic information derived from chromosome-based comparative genomic hybridization, we have reported previously on regional chromosome 7q21-q22 gains in close association with HCC progression. In this study, we undertook cDNA microarray-based comparative genomic hybridization, to examine the 7q21-q22 region for the involved gene(s) in HCC. High-resolution mapping analysis highlighted 7 candidates, namely PFTAIRE protein kinase 1 (PFTK1), ODAG, CDK6, CAS1, PEX1, SLC25A, and PEG10, within the region. H epatocellular carcinoma (HCC) is the fifth most common cancer worldwide 1 and the third most common cause of cancer-related mortality. One of the reasons for this high mortality is that the tumour usually presents at a stage when curative surgery is no longer feasible because of intrahepatic or extrahepatic metastases. Although the 5-year survival of HCC patients who have undergone hepatectomy has improved in recent years, postoperative intrahepatic recurrence can still be as high as 43% by 2 years after resection, 2 presumably because of preexisting micro-metastases. 3 These observations underscore the urgent need to understand the molecular characteristics and related biological mechanisms in tumor cell dissemination.Despite extensive studies, the underlying genomic alterations in HCC remain poorly understood, 4-6 and few tumor suppressors or proto-oncogenes have been related to metastasis and recurrences. Utilizing genetic information derived from a cohort of 100 HCC tumors analyzed by chromosome-based comparative genomic hybridization (CGH), our group has previously shown several regional chromosome gains, especially over-representations