BCL2 and neoplasm: These data indicate that 1) PDGF in the tumor microenvironment sensitizes CAF to apoptosis through changes in cellular Puma levels, 2) PDGF-mediated increases in Puma result in downstream formation of Bcl-2/Bak protein complexes, and 3) these complexes can be disrupted by BH3 mimetics, inducing Bak-dependent cell death.