Organ preferences in metastatic colony formation by spontaneous mammary carcinomas after intra-arterial inoculation.

We have demonstrated earlier that cells from some spontaneous murine mammary tumours heavily colonise the lungs of every inoculated animal when injected intravenously, whereas those from others do so weakly or not at all. Extrapulmonary deposits are rare when cells are inoculated by this route. In the current experiments, we have found that if the cells are inoculated retrograde along the subclavian artery into the arch of the aorta, or directly into the abdominal aorta, they are capable of colonising organs other than the lungs and that individual tumours have reproducible preferences for establishing colonies in certain sites. The combination of organs favoured vary from tumour to tumour but most still showed a predilection for forming pulmonary deposits. Several organs are not colonised by any tumour in any recipient. It is concluded that the distribution of metastatic colonies formed by these spontaneous mammary tumours is influenced by interplay between intrinsic properties of tumour cells, microenvironmental influences in the organs in which the cells arrest, and rheological considerations.