Figure 2. Experimental schema: transient induction of p53 in proliferating versus quiescent cells. Cells are treated (or left untreated) under different condi-tions [control (10% serum), 0% serum or rapamycin] with etoposide for 4 days. Cells are counted twice: 1) at the time of etoposide removal to measure inhibition of proliferation and 2) 6-11 days after wash to measure proliferative potential (PP). PP should not be confused with proliferation. Thus, rapamycin and 0% serum inhibit proliferation but preserve (increase) proliferative potential in etoposide-treated cells.