The purpose of this study was to determine whether production of liver metastasis by human colon carcinoma (HCC) cells depends on the response of tumor cells to organ-derived growth factors. HCC cells were isolated from several surgical specimens whose malignant potential differed (Dukes' stage B or D tumors), adapted to grow in culture, and assessed for expression of the epidermal growth factor receptor (EGF-R). Northern blot analyses revealed that highly metastatic HCC cells expressed >5-fold the number of EGF-R mRNA transcripts as low metastatic cells. The level of mRNA correlated with the amount of EGF-R protein as detected by Western blotting, immunohistochemistry, and Scatchard analyses. HCC growth response in vitro to picograms of transforming growth factor alpha was associated with functional cell surface EGF-Rs as determined by receptor tyrosine kinase activity assays. The EGF-R gene was not amplified or rearranged in highly metastatic cells. However, fluorescence in situ hybridization analysis showed that the copy number of chromosome 7 was higher in the highly metastatic cells. HCC cells were selected in vitro for low or high expression of EGF-R. Subsequent to injection into nude mice, only cells with high expression of EGF-R produced a high incidence of liver metastasis. These data demonstrate that expression of EGF-R by HCC cells directly correlates with their ability to produce hepatic metastasis.

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