CSE1L (chromosome 20 1 like) is a nuclear export receptor that mediates the re-export of importin-alpha from the nucleus to cytoplasm following cargo release 1. Beyond its canonical nucleocytoplasmic transport function, CSE1L plays critical roles in cancer progression and cellular signaling. CSE1L promotes nuclear accumulation of the transcriptional coactivator TAZ by facilitating its nuclear import through interaction with importin α5, thereby enhancing invasiveness and malignancy in human cancer cells 1. The protein is highly expressed across multiple cancer types and correlates with high cancer stage, grade, and worse patient outcomes 2. CSE1L regulates invasion and metastasis rather than proliferation, and functions as a secretory protein with higher prevalence in sera of metastatic cancer patients 2. Recent studies demonstrate CSE1L's involvement in inflammatory regulation, where it controls SP1 transcription factor nuclear translocation and activity 3. Additionally, CSE1L interacts with TRIP13 in gastric cancer, forming a bidirectional regulatory loop that stabilizes both proteins and promotes tumor progression 4. CSE1L's phosphorylation is regulated by ERK signaling, positioning it as a potential biomarker for monitoring drug resistance in targeted cancer therapy 5.