SOX2 and pancreatic ductal adenocarcinoma: It had been reported that CDK1 interacts with SOX2 to promote tumor initiation in human melanoma and colon [10], and patients with overexpression of CDK1 were reported to have poor prognosis in epithelial ovarian cancer [43], pancreatic ductal adenocarcinoma [11], lung adenocarcinoma [44] and might be a relevant prognostic biomarker.