BCL2 and neoplasm: Although macrophages and IL-1β protected tumor cells from TRAIL-induced apoptosis, they did not regulate the levels of the bcl-2 family members in tumor cells, such as Bcl-x or Mcl1, or alter the expression of cIAPs, which have been shown to modulate the response of cells to TRAIL-induced apoptosis [16] (data not shown).