Primary lung carcinoma cells display low gap junctional, intercellular communication. a and b: Cells cultured from a freshly explanted lung tumor specimen were grown in electroporation chambers and Lucifer yellow introduced with an electrical pulse (Figure 7, ). Arrows point to the edge of the electroporated area. Note the absence of gap junctional communication. Magnification: 240x. c and d: Following growth of the cells for 10 weeks, fibroblasts present in the original cell suspension predominated. They were plated in electroporation chambers and Lucifer yellow introduced with an electrical pulse. Note the extensive communication through gap junctions. Lower panel Extracts of cells cultured from a moderately differentiated adenosquamous carcinoma, a poorly differentiated adenocarcinoma, and adenocarcinoma, respectively (lanes 1–3), or E10 cells (lane 4), were probed for Src-ptyr418 or GAPDH as a loading control, as indicated.