Site-induced differences in spontaneous metastasis of MO4 mouse fibrosarcoma cells

MO4 mouse fibrosarcoma cells metastasized to the lungs and to the regional lymph nodes from a subcutaneous tumour in the pinna when they were derived from a tumour in the tail or from lung metastases. In contrast, no metastases were found when MO4 cells were derived from a tumour in the pinna or from the parent cell line. Cells from tumours in the pinna produced metastatic tumours when they were implanted in the tail but not in the pinna. The type of implant-spheroidal cell aggregate, freshly cut tumour fragment or precultured tumour fragment- had no influence on the metastatic behaviour of the resulting tumour. These observations confirm the concept that local factors at the growth site of a tumour influence the metastatic behaviour of that tumour.