Transplant of C4-HI tumor growing in BALB/c-GFP mice into BALB/c mice. Mice were sacrificed 7 days (A) or 13 days (B-D) after transplantation. Before sacrifice animals were perfused as described in Materials and Methods and cryostat sections were obtained. (A-B) Endogenous GFP labeling was detected under a confocal microscope. (C) Primary cultures of 13-day tumors were seeded on chamber slides and CAF-HI were immunostained for SMA (red). Original magnification: 400×; Bar: 45 μm. (D) Cryostat sections of 13-day tumors were immunostained for SMA (green). Nuclei were counterstained with PI. Original magnification: 200×; Bar: 60 μm.