Among the genes identified, in a comparison of the global gene expression profile of metastatic colorectal cancer to that of primary cancers, benign colorectal tumors, and normal colorectal epithelium, the PRL-3 protein tyrosine phosphatase gene was of particular interest. It was expressed at high levels in each of 18 cancer metastases studied but at lower levels in non-metastatic tumors and normal colorectal epithelium. In three of twelve metastases examined, multiple copies of the PRL-3 gene were found within a small amplicon located at chromosome 8q24.3. These data suggest that the PRL-3 gene is important for colorectal cancer metastasis and provides a new therapeutic target for these intractable lesions.