Metastatic potential of metastases, tumor cell heterogeneity, and therapeutic implications.

The metastasizing capacity of spontaneous metastases of several murine tumors of different histology, origin, and disseminative pattern was investigated to test the hypothesis that metastases originate from various subpopulations within the primary tumor. Overall, tumor cells from individual metastases did not show greater metastasizing capacity than the cells of the original tumor, although a degree of heterogeneity was seen. Differences in the immunologic profile among metastases of the same tumor were also observed. The possible therapeutic implications of these findings are discussed.