Fig. (2) Results of clonogenic assays of rhEGF-treated cells.(a) AMC-HN3, (b) A549, (c) EMT-6, (d) normal cervix fibroblast.The cells were incubated for 24 hours prior to treatment with 0, 0.01, 0.1, 1, 10, 100, or 1000 nM rhEGF. After 10 days of incubation at 37 °C, colonies were counted. In the AMC-HN3 cells, the number of colonies decreased as the rhEGF concentration increased. In contrast, rhEGF increased the number of colonies formed from normal fibroblasts.