I gonna start western blotting to see the expression of apoptosis activators (Bcl-2, Bax, Caspase-3,7 & 9 etc..). Recently I have referred some literatures regarding apoptosis, in their results of western blot I saw constant expression of Bax, pro-caspase-3 and others in control group (Untreated A549 cells) too. I am little confused with this because, usually cancer cells evade Apoptosis. It could be induced by treating with drugs or compound of interest. Then how expression (apoptosis execution genes) occurs in untreated control group? Kindly clarify my doubt... If it is normal fact pls suggest some literature to clarify my doubt..