CYCS and B-cell chronic lymphocytic leukemia: Bcl-2 family plays a crucial role in the endogenous apoptosis signal transduction pathway by regulating the mitochondrial/cytochrome C-mediated apoptosis process.356,357 This family consists of anti-apoptotic and pro-apoptotic proteins that act synergistically as apoptotic switches, ultimately determining the cell’s fate.358–360 Among them, Bcl-2 is an anti-apoptotic protein that is highly expressed in various hematological malignancies, including chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), making it an attractive drug target.