BAK1 and mantle cell lymphoma: BAX and BAK's presence on the mitochondrial membrane is needed for the release of cytochrome c to the cytoplasm allowing for the activation of caspases during apoptosis.16, 37, 38, 39, 40 Downregulation of Bcl‐2 has been shown to increase apoptosis in mantle cell lymphoma cells treated with immunotoxins in vitro.41 Other studies have demonstrated that Mcl‐1 downregulation increases apoptosis in a variety of cancers.37, 42, 43