Intrabronchial implantation of the Lewis lung tumor cell does not favor tumorigenicity and metastasis.

The purpose of these studies was to determine whether the orthotopic implantation of the Lewis lung tumor favors tumorigenicity and production of metastasis as compared with implantation at an ectopic site. Different numbers of viable cells were implanted subcutaneously (footpad), intrabronchially, or intrathoracically into groups of syngeneic mice. Tumorigenicity, production of distant metastases and survival were recorded. Tumor cells implanted subcutaneously produced fast-growing local tumors and numerous spontaneous lung metastases. Tumor cells implanted intrabronchially produced slow-growing tumors that did not produce distant metastasis. Since radiolabeled cells implanted into different sites exhibited similar patterns of survival, the differences in behavior of 3LL cells in the skin or lung were due to other factors. We conclude that for the Lewis lung carcinoma, orthotopic implantation does not favor increased tumorigenicity and metastatic potential.