Influence of transplantation site on metastatic ability of mouse bladder carcinoma sublines

The influence of the primary implantation site on the metastatic behavior of a murine transitional cell carcinoma line (MBT-2) and three metastatic sublines (L3F1, L3F2, and L3F3) was studied. The parent MBT-2 cell line produced a low incidence of lung metastasis after intravenous injection and no metastases from the primary tumor when injected either subcutaneously in the right hind flank or in the footpad. Intramuscular implantation of the MBT-2 cells in the right hind flank resulted in a significant increase over the subcutaneous, footpad, and intravenous sites in the incidence and number of lung metastases. Three in vivo/in vitro selected metastatic sublines (L3F1, L3F2, and L3F3) were highly metastatic when injected subcutaneously, intramuscularly, and intravenously. A low number of pulmonary metastases was observed after footpad implantation of the three sublines. This study demonstrated a definite implantation site-influence on the metastatic ability of the parent MBT-2 line and the three selected sublines. Intramuscular implantation was the most permissive implantation site for the development of spontaneous metastasis for the MBT-2 line and the L3F1, L3F2, and L3F3 sublines.