XPO1 and cancer: The nuclear protein exportin 1 (XPO1; also called CRM1) has an essential role in protein trafficking that functions as a nucleocytoplasmic regulator of key transcription factors.30, 31 Recently, direct pharmacological inhibition of XPO1 has been shown to be effective in several types of cancers.32, 33, 34, 35 XPO1 also has been demonstrated to interact with polyglutamine (polyQ) proteins that are produced from expanded nucleotide repeats in disorders such as Huntington’s.36