The collection of the motile population of cells from a living tumor

In this study, we report that needles containing chemoattractants can be us ed to collect the subpopulation of motile and chemotactic tumor cells from a primary tumor in a live rat as a pure population suitable for further ana lysis. The most efficient cell collection requires the presence of chemotac tic cytokines, such as epidermal growth factor and serum components, and oc curs with W-fold higher efficiency in metastatic tumors compared with nonme tastatic tumors. Although tumor cells of the nonmetastatic tumors show a mo tility response to serum, they were not collected with high efficiency into needles in vivo in response to serum, indicating that additional factors b esides motility are required to explain differences in cell collection effi ciencies between metastatic and nonmetastatic tumors, The results reported here indicate that needles filled with growth factors and matrigel, when in serted into the primary tumor, can faithfully mimic the environment that su pports invasion and intravasation in vivo. Furthermore, the results indicat e that the same fell behaviors that contribute to chemotaxis in vitro also contribute to invasion in vivo.