The central regulators within the intrinsic apoptotic pathway belong to the Bcl-2 protein family, whose members are strongly interconnected; the Bcl-2 family containing pro-apoptotic (Bid, Bad, Bax, and Bak) and anti-apoptotic proteins (Bcl-2, Bcl-XL, Mcl-1, Bcl-w, and A1/Bfl1) often display a deregulation in cancer, and their targeting has triggered the development of new anticancer agents [51]. Here, BID is linked to cancer.