<prompt> All of the following trigger the intrinsic pathway of programmed cell death, except:Withdrawal of growth factor stimulusRadiation injuryActivation of Fas receptor by FasLIntracellular protein misfolding  <response>: Apoptosis is also referred to as programmed cell death. Mitochondrial Intrinsic pathway of apoptosis is triggered due to cellular injury caused by: Growth factor withdrawal DNA damage by radiation, toxins, free radicals Protein misfolding ER stress Death receptor Extrinsic pathway of apoptosis is triggered by activation of Fas and TNF receptors. The ligand for Fas receptor is called Fas ligand FasL. FasL is expressed on T cells that recognize self antigens and on some CTLs that kill virus-infected and tumor cells. 