Podoplanin and SOX2 expression in esophageal squamous cell carcinoma after neoadjuvant chemo-radiotherapy

Neoadjuvant chemo-radiotherapy (CRT) followed by surgery are the standard approaches for locally advanced esophageal cancer. However, the overall cure rate is very low. The aim of this preliminary study was to evaluate the expression of podoplanin and SOX2 known as stemness markers for esophageal squamous cell carcinoma (ESCC) and their association with clinical outcome. We obtained a total of 20 specimens from patients with ESCC who underwent neoadjuvant CRT (30-40 Gy; 5-fluorouracil plus cisplatin) followed by surgery. Podoplanin and SOX2 expression was evaluated using immunohistochemistry and the association of their expressions with clinicopathological variables was investigated. Podoplanin and SOX2 staining was detected not only in residual cancer cells, but also in the basal layer of adjacent normal mucosa after neoadjuvant CRT. High expression of podoplanin was correlated with lymph node metastasis, advanced postoperative stage and vascular invasion (P<0.05), while, high expression of SOX2 was correlated with lymphatic, vascular invasion, poor differentiated tumor and incomplete resection (P<0.05). High expression of podoplanin was significantly associated with poor overall survival (P<0.05). In conclusion, the expression levels of podoplanin and SOX2 expression may be useful prognostic markers for ESCC treated with neoadjuvant CRT.