[Bi-213]anti-CD20 is a promising radioimmunoconjugate to improve therapeutic success by breaking radio- and chemoresistance in CD20-expressing NHL cells via re-activating apoptotic pathways through reversing deficient activation of caspases and downregulation of XIAP and Bcl-xL. This evidence concerns the gene BCL2L1 and non-Hodgkin lymphoma.