While the development of T-cell lymphomas and Beclin-1 heterozygosity in Atm−/− mice is also associated with tumor development, Valentin-Vega et al. unexpectedly observed that the allelic loss of Beclin-1 in Atm−/− mice increased survival to 262 days compared to 137 days in Atm−/− mice. Here, BECN1 is linked to T-cell non-Hodgkin lymphoma.