Dongsheng Yue, Changli Wang

Department of Lung Cancer, Tianjin MedicalUniversity Cancer Institute and Hospital, Tianjin.

Objective：Squamouscell carcinomas (SCC) account for approximately 30% of non-small cell lungcancer (NSCLC). Current stagingmethods do not adequately predict outcome forthis disease. EMX2 is ahomeo-domain-containing transcription factor known toregulate a key developmentalpathway. This study assessed the significance ofEMX2 as a prognostic and predictive marker for resectable lung SCC. Method：Twoindependent cohorts of patients with lung SCC undergoing surgical resectionwere studied. EMX2 protein expression was examined by immunohistochemistry, Westernblot, or immunofluorescence. EMX2 expression levels in tissue specimens werescored and correlated with patientoutcomes. Chemo-sensitivity of lung SCC celllines stably transfected with EMX2 shRNAs to cisplatin, carboplatin, anddocetaxol was examined in vitro. Result：EMX2expression was down-regulated in lung SCC tissue samples compared to theirmatched adjacent normal tissues. Positive EMX2 expression was significantlyassociated with improved overall survival instage I lung SCC patients, and instage II/IIIA lung SCC patients receiving adjuvant chemotherapy. EMX2expression was also associated with expression of EMT markers in both lung SCCcell lines and tissue samples. Knock-down of EMX2 expression in lung SCC cellspromoted chemo-resistance and cell migration. Conclusion：EMX2expression is down-regulated in lung SCC and its down-regulation is associatedwith chemo-resistance in lung SCC cells, possibly through regulation ofEpithelial-to- Mesenchymal Transition (EMT). EMX2 may serve as a novel prognosticmarker for stage I lung SCC patients and a prediction marker for stage II/IIIAlung SCC patients receiving adjuvant chemotherapy.

Keywords：EMX2 lung SCC  Epithelial-to-Mesenchymal Transition