Figure 2.

Mouse lung colonization by GFP human lung tumor cells in histoculture. (A) Growth of the tumor cells seeded in the mouse lung after 6 days of histoculture. The tumor colonies still remain as microcolonies with an average size of approximately 90 μm. By day 14, however, the tumor colonies had grown very significantly and occupied a significant fraction of the lung, with the largest individual colony being approximately 400 μm across its largest diameter (B). By day 24, very brightly fluorescing tumor colonies had grown to occupy approximately one-half of the histocultured lung, with sizes up to 750 μm (C). A parallel, 24-day histocultured lung had brightly fluorescing tumor colonies that invaded the supporting sponge-gel matrix as well as the lung itself (E). (D) At 52 days of histoculture, the tumor colonies have grown more on the histocultured mouse lung, with perhaps a secondary layer of colonies forming a structure on top of the first layer of colonies. The colonies were differentiating rather than expanding at this point. Satellite colonies by then had grown into the supporting sponge-gel matrix (Bar = 500 μm.)