IGFBP5 influences BCL2 expression. LX2 cells were transfected with control small interfering RNA (siCtrl) or IGFBP5 siRNA (siBP5). Sixteen hours after transfection the medium was replaced by serum-free medium. Recombinant IGFBP5 was added at t = 24 h and 45 h, after replacing the medium, to siIGFBP5 transfected cells (siBP5+rBP5). After 48 h RNA was isolated from control (siCtrl), silenced (siBP5), silenced treated with rIGFBP5 (siBP5+rBP5) and LX2 cells overexpression IGFBP5 (LX2(BP5)) and used for quantitative polymerase chain reaction in order to determine BCL2 mRNA. The BCL2 mRNA levels were normalized to 36B4 and given as a percentage of control cells.