Effect of EGR and CP55,940 upon the intracellular signalling of human PC-3 prostate cancer cells. Cells were treated for two weeks without medium change in the absence or presence of 10 ng/ml EGF. Vehicle or 100 nM CP55,940 (“CP”) was then added and the cells were incubated for a further week. Cut-offs (shown by the red lines in Figure 3) were used to define the number and hence % of cells in the four quadrants. (means ± s.e.m., n = 7). P values given in the figures refer to one-way repeated measure ANOVAs not assuming sphericity. **P < 0.01, Tukey’s multiple comparison test following significant ANOVA.