Beclin-1 (BECN1), also known as ATG6 or VPS30, has a central role in autophagy, a process of programmed cell survival, which is increased during periods of cell stress and extinguished during the cell cycle. Beclin-1, may play a role in antiviral host defense. It protects against infection by a neurovirulent strain of Sindbis virus. Beclin-1 participates in the regulation of autophagy and has an important role in development, tumorigenesis, and neurodegeneration. A progressively reduced Beclin-1 expression is reported to correlate with the primary tumor growth of squamous cell carcinoma and adenocarcinoma of the lung. Caspase-mediated cleavage of Beclin 1 promotes crosstalk between apoptosis and autophagy.