BCL2 and Alzheimer disease: Apoptosis intricately collaborates with numerous critical factors in AD pathology, encompassing both pro-apoptotic and anti-apoptotic elements such as B-cell lymphoma 2 (Bcl2), Bcl2-associated death promoter, amyloid precursor protein intracellular C-terminal domain, caspases, tumor necrosis factor-alpha (TNF-α), Bcl2-associated X protein (Bax), amyloid-beta (Aβ), enzyme activity, and reactive oxygen species production.