In adequate tumor surgery of chemically induced soft tissue sarcomas--an experimental approach for induction of metastasis formation?

In preceding experiments with nude mice bearing xenotransplanted soft tissue sarcomas after inoculation of cultured sarcoma cells we attained a high percentage of metastatic dissemination by repeated inadequate tumor surgery. In the study presented here we used methylcholanthrene induced sarcomas (rhabdomyosarcomas and undifferentiated sarcomas in part showing the picture of storiform/pleomorphic malignant fibrous histiocytomas) which were produced in NMRI mice and examined (1) whether or not metastasis formation could be triggered or enhanced by repeated inadequate tumor surgery in these animals, and (2) the efficacy of the same surgical procedure following xenotransplantation of the tumors into nude mice. We did not reach an increasing frequency with both experimental arrangements. After discussing several factors which could be in general responsible for inducing metastasis formation and after comparing the results of our several experiments it is suggested that the methylcholanthrene induced soft tissue tumors may not contain cell clones able to metastasize.