Fig. (3) Effects of rhEGF on cell killing of ionizing radiation.(a) AMC-HN3, (b) A549, (c) EMT-6, (d) normal cervix fibroblast.Cells were simultaneously irradiated and treated with rhEGF (10nM). After 24 hours, the medium was removed, and cells were incubated in drug-free media for 10 days to form colonies. rhEGF radiosensitized AMC-HN3 cells, but protected normal fibroblasts from the killing effect of radiation.