Lenalidomide binds directly to cereblon, a component of the ubiquitin ligase enzyme complex EZ, which includes damaged deoxyribonucleic acid (DNA)-binding protein 1 (DDB 1), culin 4 (CUL4), and regulator of culin 1 (Rocl). In hematopoietic cells, lenalidomide binds cereblon to accumulate the substrate proteins Aiolos and Ikaros, which are lymphoid transcription factors, leading to their ubiquitination and subsequent degradation, resulting in direct cytotoxic and immunomodulatory effects.