Inhibition of apoptosis in FDC2–wt-ER cells by SCF and Epo is not subject to synergy. Based on the observed synergy of SCF and Epo costimulated mitogenesis in FDC2–wt-ER cells (Fig 3, above) studies were performed to test whether this might involve effects on the inhibition of apoptosis. FDC2–wt-ER cells in Optimem medium, 1% FBS were cultured for 7 hours in the presence of SCF (33 ng/mL or 1 nmol/L), and in the presence or absence of Epo (Epo₂ 25 U/mL or 5 nmol/L, Epo₁ 10 U/mL or 2 nmol/L). Apoptosis then was assayed based on levels of intranucleosomal DNA fragmentation and products were analyzed quantitatively by phosphor-imaging. Values are means of three independent scans (±SE).