IKZF1 and plasma cell myeloma: All three IMiD drugs promote the degradation of two hematopoietic transcription factors IKZF1 and IKZF3 to achieve anti-myeloma activity (Krönke et al., 2014) (Lu et al., 2014a) (Gandhi et al., 2014), whereas only LEN targets CK1α for effective degradation (Krönke et al., 2015), which is presumably linked to its efficacy in myelodysplastic syndrome with chromosome 5q deletion.