Different metastatic potential of in vitro and in vivo lines selected from Lewis lung carcinoma: correlation with response to different bleomycin schedulings.

In vitro and in vivo variant cell lines selected from Lewis lung carcinoma are described. In vitro tumor lines are shown to differ in their metastatic potential, evaluated as lung colony-forming ability. Moreover, corresponding in vivo sublines, derived from intramuscular implant of cultured tumor cells, exhibit the same behavior for metastases formation as their in vitro counterpart. The metastatic potential of the in vivo lines has been evaluated both as lung colony-forming ability and as spontaneous metastasis formation. Response to bleomycin (BLM) treatment has been studied on the in vitro and the in vivo lines. Results reported show that the most metastatic lines, in vitro and in vivo, appear to be more resistant to a BLM treatment and that appropriate fractionation regimens can improve both the percentage of cell kill and the percentage of metastases reduction.