AGR2 expression as a predictive biomarker for therapy response in esophageal squamous cell carcinoma

Despite multidisciplinary therapy, the prognosis is poor for esophageal squamous cell carcinoma (ESCC). In the locally advanced stage, neoadjuvant chemoradiotherapy (nCRT) followed by surgery could provide survival benefits to some patients. Here, we aimed to identify for tumor therapy response a biomarker based on RNA sequencing. We collected endoscopic biopsies of 32 ESCC patients, who were divided according to nCRT response, into two groups: the complete response group (n  =  13) and the non-complete response group (n  =  19). RNA-sequencing data showed that 464 genes were differentially expressed. Increased in non-complete response group, 4 genes increased expressions were AGR2 (anterior gradient 2), GADD45B (growth arrest and DNA damage inducible beta), PPP1R15A (protein phosphatase 1 regulatory subunit 15A) and LRG1 (leucine rich alpha-2-glycoprotein 1). The areas under the curve (AUC) of the AGR2 gene was 0.671 according to read counts of RNA-seq and therapy response of nCRT. In vitro study showed that apoptosis cell was significantly increased in the AGR2-knockdown TE-2 cell line treated with cisplatin and 5-Fluorouracil (5-FU), when compared with si-control. Results suggest that in ESCC, the AGR2 gene is a promising and predictive gene marker for the response to anti-tumor therapy.