B-Cell Lymphoma 2 (BCL2) is a member of the Bcl-2 family of proteins that regulate cell apoptosis by controlling mitochondrial permeability and release of cytochrome c. BCL2 also has critical roles in normal cell physiology related to neuronal activity, autophagy, calcium handling, mitochondrial dynamics and energetics, and other processes of normal healthy cells which intertwine with its apoptotic functions to link cell growth to cell death. BCL2 overexpression has been shown to promote cell survival by suppressing apoptosis, and is found to be correlated with poor disease prognosis in breast, prostate, ovarian, endometrial and colon cancers. In follicular lymphoma, Anti-BCL2 reacts negatively with germinal centers and positively with neoplastic follicles. In lymphoid lesions, BCL2 staining is useful for distinguishing reactive and neoplastic follicular proliferations, and for identifying minimal residual disease in the bone marrow of follicular lymphoma patients. BCL2 is now a useful target of human cancer therapy.