{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Bcl-2 is an integral outer mitochondrial membrane protein whose major function appears to be inhibition of programmed cell death (apoptosis) and prolong cell survival by arresting cells in the G0/G1 phase of the cell cycle. The ratio of death antagonists (Bcl-2, Bcl-XL, Bcl-W, Mcl-1, A1) to agonists (Bax, Bak, Bcl-Xs, Bad, Bid) determines whether a cell will respond to an apoptotic signal. The Bcl-2 protein is expressed in foetal tissues and basal cells of human epithelia, which suggests a role in normal growth regulation and differentiation. Research shows that constitutive expression of Bcl-2, such as in the case of translocation of BCL2to Ig heavy-chain loci, is thought to be the cause of follicular lymphoma."}]}]}