Liver-colonizing melanoma cells selected from B-16 melanoma.

Liver-colonizing tumor cells were selected from B-16 melanoma by a stepwise procedure: (1) injection of the original cells through the portal circulation: (2) removal of tumor cells from the hepatic tumor nodules for culture in vitro; (3) reinjection of such cells through the portal circulation and repetition of steps 2 and 3 eight times. The predilection of these cells to form tumors in the liver was clearly demonstrated following injection of the cells intra-arterially. The accuracy of the injection technique was controlled by monitoring amonts of injected radioactively labelled Sephadex microspheres. This liver-colonizing preference was not exclusive, but relative.