Primary cultures of C4-HI tumors growing in BALB/c-GFP mice. CAF-HI-GFP were isolated as described in Materials and Methods. (Upper panel) Photograph of a primary culture of isolated CAF-HI-GFP alone or, (lower panel) combined with EPI-HI cells. Notice that epithelial neoplastic cells are negative for GFP. Original magnification: 100×; Bar: 30 μm. (upper panel) and 40× Bar: 75 μm (lower panel).