CDKN1B and thyroid cancer: The majority of thyroid cancers exhibit reduced nuclear FoxO3A (10), and FoxO3A downstream target genes CDKN1B encoding cyclin-dependent kinase inhibitor p27KIP1, and BCL2L11 encoding Bim, a pro-apoptotic member of the Bcl-2 family of proteins, have been identified as functionally relevant in follicular rat thyroid cells (10) (Figure 1).