Morphogenic activity of rHuEpo. EA.hy926 cells were seeded on Matrigel and incubated in DMEM added with 0.1% BSA (A) or with 0.5 U/mL (B), 1.0 U/mL (C), or 2.0 U/mL (D) rHuEpo. After 6 hours, cells were photographed using an inverted phase contrast photomicroscope. A dose-dependent morphogenetic effect of rHuEpo was observed.