SHP1 induced no significant apoptosis. In addition to the lack of an increase in the sub-G_0/1 cell population, SHP1 expression in SU-DHL-1 cells also did not lead to detectable cleaved PARP product (arrow) and active caspase-3. Nontransfected SU-DHL-1 cells treated with different doses of doxorubicin served as positive controls.