Inhibition of SKT6 cell proliferation via C-terminal truncated chimeric receptor forms. To test possible effects of EGF (or Epo as an internal control) on SKT6-EE483, -EE372, and -EENb2 cell proliferation, cells were cultured for 48 hours in the presence of Epo (upper panel, solid symbols) or EGF (lower panel, open symbols) at increasing concentrations. Rates of [methyl-³H] thymidine ([³H]dT) incorporation then were assayed. Graphed are the normalized mean rates of [³H]dT incorporation (n = 3).